diff --git a/packages/google-cloud-dataproc/src/v1/autoscaling_policy_service_client.ts b/packages/google-cloud-dataproc/src/v1/autoscaling_policy_service_client.ts
index c323b1645a2..00e504bb707 100644
--- a/packages/google-cloud-dataproc/src/v1/autoscaling_policy_service_client.ts
+++ b/packages/google-cloud-dataproc/src/v1/autoscaling_policy_service_client.ts
@@ -37,8 +37,13 @@ export class AutoscalingPolicyServiceClient {
   private _innerApiCalls: {[name: string]: Function};
   private _pathTemplates: {[name: string]: gax.PathTemplate};
   private _terminated = false;
+  private _opts: ClientOptions;
+  private _gaxModule: typeof gax | typeof gax.fallback;
+  private _gaxGrpc: gax.GrpcClient | gax.fallback.GrpcClient;
+  private _protos: {};
+  private _defaults: {[method: string]: gax.CallSettings};
   auth: gax.GoogleAuth;
-  autoscalingPolicyServiceStub: Promise<{[name: string]: Function}>;
+  autoscalingPolicyServiceStub?: Promise<{[name: string]: Function}>;
 
   /**
    * Construct an instance of AutoscalingPolicyServiceClient.
@@ -62,8 +67,6 @@ export class AutoscalingPolicyServiceClient {
    *     app is running in an environment which supports
    *     {@link https://developers.google.com/identity/protocols/application-default-credentials Application Default Credentials},
    *     your project ID will be detected automatically.
-   * @param {function} [options.promise] - Custom promise module to use instead
-   *     of native Promises.
    * @param {string} [options.apiEndpoint] - The domain name of the
    *     API remote host.
    */
@@ -91,28 +94,31 @@ export class AutoscalingPolicyServiceClient {
     // If we are in browser, we are already using fallback because of the
     // "browser" field in package.json.
     // But if we were explicitly requested to use fallback, let's do it now.
-    const gaxModule = !isBrowser && opts.fallback ? gax.fallback : gax;
+    this._gaxModule = !isBrowser && opts.fallback ? gax.fallback : gax;
 
     // Create a `gaxGrpc` object, with any grpc-specific options
     // sent to the client.
     opts.scopes = (this.constructor as typeof AutoscalingPolicyServiceClient).scopes;
-    const gaxGrpc = new gaxModule.GrpcClient(opts);
+    this._gaxGrpc = new this._gaxModule.GrpcClient(opts);
+
+    // Save options to use in initialize() method.
+    this._opts = opts;
 
     // Save the auth object to the client, for use by other methods.
-    this.auth = (gaxGrpc.auth as gax.GoogleAuth);
+    this.auth = (this._gaxGrpc.auth as gax.GoogleAuth);
 
     // Determine the client header string.
     const clientHeader = [
-      `gax/${gaxModule.version}`,
+      `gax/${this._gaxModule.version}`,
       `gapic/${version}`,
     ];
     if (typeof process !== 'undefined' && 'versions' in process) {
       clientHeader.push(`gl-node/${process.versions.node}`);
     } else {
-      clientHeader.push(`gl-web/${gaxModule.version}`);
+      clientHeader.push(`gl-web/${this._gaxModule.version}`);
     }
     if (!opts.fallback) {
-      clientHeader.push(`grpc/${gaxGrpc.grpcVersion}`);
+      clientHeader.push(`grpc/${this._gaxGrpc.grpcVersion}`);
     }
     if (opts.libName && opts.libVersion) {
       clientHeader.push(`${opts.libName}/${opts.libVersion}`);
@@ -122,7 +128,7 @@ export class AutoscalingPolicyServiceClient {
     // For browsers, pass the JSON content.
 
     const nodejsProtoPath = path.join(__dirname, '..', '..', 'protos', 'protos.json');
-    const protos = gaxGrpc.loadProto(
+    this._protos = this._gaxGrpc.loadProto(
       opts.fallback ?
         require("../../protos/protos.json") :
         nodejsProtoPath
@@ -132,16 +138,16 @@ export class AutoscalingPolicyServiceClient {
     // identifiers to uniquely identify resources within the API.
     // Create useful helper objects for these.
     this._pathTemplates = {
-      projectLocationAutoscalingPolicyPathTemplate: new gaxModule.PathTemplate(
+      projectLocationAutoscalingPolicyPathTemplate: new this._gaxModule.PathTemplate(
         'projects/{project}/locations/{location}/autoscalingPolicies/{autoscaling_policy}'
       ),
-      projectLocationWorkflowTemplatePathTemplate: new gaxModule.PathTemplate(
+      projectLocationWorkflowTemplatePathTemplate: new this._gaxModule.PathTemplate(
         'projects/{project}/locations/{location}/workflowTemplates/{workflow_template}'
       ),
-      projectRegionAutoscalingPolicyPathTemplate: new gaxModule.PathTemplate(
+      projectRegionAutoscalingPolicyPathTemplate: new this._gaxModule.PathTemplate(
         'projects/{project}/regions/{region}/autoscalingPolicies/{autoscaling_policy}'
       ),
-      projectRegionWorkflowTemplatePathTemplate: new gaxModule.PathTemplate(
+      projectRegionWorkflowTemplatePathTemplate: new this._gaxModule.PathTemplate(
         'projects/{project}/regions/{region}/workflowTemplates/{workflow_template}'
       ),
     };
@@ -151,11 +157,11 @@ export class AutoscalingPolicyServiceClient {
     // pages). Denote the keys used for pagination and results.
     this._descriptors.page = {
       listAutoscalingPolicies:
-          new gaxModule.PageDescriptor('pageToken', 'nextPageToken', 'policies')
+          new this._gaxModule.PageDescriptor('pageToken', 'nextPageToken', 'policies')
     };
 
     // Put together the default options sent with requests.
-    const defaults = gaxGrpc.constructSettings(
+    this._defaults = this._gaxGrpc.constructSettings(
         'google.cloud.dataproc.v1.AutoscalingPolicyService', gapicConfig as gax.ClientConfig,
         opts.clientConfig || {}, {'x-goog-api-client': clientHeader.join(' ')});
 
@@ -163,15 +169,33 @@ export class AutoscalingPolicyServiceClient {
     // of calling the API is handled in `google-gax`, with this code
     // merely providing the destination and request information.
     this._innerApiCalls = {};
+  }
+
+  /**
+   * Initialize the client.
+   * Performs asynchronous operations (such as authentication) and prepares the client.
+   * This function will be called automatically when any class method is called for the
+   * first time, but if you need to initialize it before calling an actual method,
+   * feel free to call initialize() directly.
+   *
+   * You can await on this method if you want to make sure the client is initialized.
+   *
+   * @returns {Promise} A promise that resolves to an authenticated service stub.
+   */
+  initialize() {
+    // If the client stub promise is already initialized, return immediately.
+    if (this.autoscalingPolicyServiceStub) {
+      return this.autoscalingPolicyServiceStub;
+    }
 
     // Put together the "service stub" for
     // google.cloud.dataproc.v1.AutoscalingPolicyService.
-    this.autoscalingPolicyServiceStub = gaxGrpc.createStub(
-        opts.fallback ?
-          (protos as protobuf.Root).lookupService('google.cloud.dataproc.v1.AutoscalingPolicyService') :
+    this.autoscalingPolicyServiceStub = this._gaxGrpc.createStub(
+        this._opts.fallback ?
+          (this._protos as protobuf.Root).lookupService('google.cloud.dataproc.v1.AutoscalingPolicyService') :
           // tslint:disable-next-line no-any
-          (protos as any).google.cloud.dataproc.v1.AutoscalingPolicyService,
-        opts) as Promise<{[method: string]: Function}>;
+          (this._protos as any).google.cloud.dataproc.v1.AutoscalingPolicyService,
+        this._opts) as Promise<{[method: string]: Function}>;
 
     // Iterate over each of the methods that the service provides
     // and create an API call method for each.
@@ -190,9 +214,9 @@ export class AutoscalingPolicyServiceClient {
           throw err;
         });
 
-      const apiCall = gaxModule.createApiCall(
+      const apiCall = this._gaxModule.createApiCall(
         innerCallPromise,
-        defaults[methodName],
+        this._defaults[methodName],
         this._descriptors.page[methodName] ||
             this._descriptors.stream[methodName] ||
             this._descriptors.longrunning[methodName]
@@ -206,6 +230,8 @@ export class AutoscalingPolicyServiceClient {
         return apiCall(argument, callOptions, callback);
       };
     }
+
+    return this.autoscalingPolicyServiceStub;
   }
 
   /**
@@ -327,6 +353,7 @@ export class AutoscalingPolicyServiceClient {
     ] = gax.routingHeader.fromParams({
       'parent': request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.createAutoscalingPolicy(request, options, callback);
   }
   updateAutoscalingPolicy(
@@ -389,6 +416,7 @@ export class AutoscalingPolicyServiceClient {
     ] = gax.routingHeader.fromParams({
       'policy.name': request.policy!.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.updateAutoscalingPolicy(request, options, callback);
   }
   getAutoscalingPolicy(
@@ -457,6 +485,7 @@ export class AutoscalingPolicyServiceClient {
     ] = gax.routingHeader.fromParams({
       'name': request.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.getAutoscalingPolicy(request, options, callback);
   }
   deleteAutoscalingPolicy(
@@ -526,6 +555,7 @@ export class AutoscalingPolicyServiceClient {
     ] = gax.routingHeader.fromParams({
       'name': request.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.deleteAutoscalingPolicy(request, options, callback);
   }
 
@@ -616,6 +646,7 @@ export class AutoscalingPolicyServiceClient {
     ] = gax.routingHeader.fromParams({
       'parent': request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.listAutoscalingPolicies(request, options, callback);
   }
 
@@ -670,6 +701,7 @@ export class AutoscalingPolicyServiceClient {
       'parent': request.parent || '',
     });
     const callSettings = new gax.CallSettings(options);
+    this.initialize();
     return this._descriptors.page.listAutoscalingPolicies.createStream(
       this._innerApiCalls.listAutoscalingPolicies as gax.GaxCall,
       request,
@@ -882,8 +914,9 @@ export class AutoscalingPolicyServiceClient {
    * The client will no longer be usable and all future behavior is undefined.
    */
   close(): Promise<void> {
+    this.initialize();
     if (!this._terminated) {
-      return this.autoscalingPolicyServiceStub.then(stub => {
+      return this.autoscalingPolicyServiceStub!.then(stub => {
         this._terminated = true;
         stub.close();
       });
diff --git a/packages/google-cloud-dataproc/src/v1/cluster_controller_client.ts b/packages/google-cloud-dataproc/src/v1/cluster_controller_client.ts
index 7d78198c165..c238842555b 100644
--- a/packages/google-cloud-dataproc/src/v1/cluster_controller_client.ts
+++ b/packages/google-cloud-dataproc/src/v1/cluster_controller_client.ts
@@ -37,9 +37,14 @@ export class ClusterControllerClient {
   private _innerApiCalls: {[name: string]: Function};
   private _pathTemplates: {[name: string]: gax.PathTemplate};
   private _terminated = false;
+  private _opts: ClientOptions;
+  private _gaxModule: typeof gax | typeof gax.fallback;
+  private _gaxGrpc: gax.GrpcClient | gax.fallback.GrpcClient;
+  private _protos: {};
+  private _defaults: {[method: string]: gax.CallSettings};
   auth: gax.GoogleAuth;
   operationsClient: gax.OperationsClient;
-  clusterControllerStub: Promise<{[name: string]: Function}>;
+  clusterControllerStub?: Promise<{[name: string]: Function}>;
 
   /**
    * Construct an instance of ClusterControllerClient.
@@ -63,8 +68,6 @@ export class ClusterControllerClient {
    *     app is running in an environment which supports
    *     {@link https://developers.google.com/identity/protocols/application-default-credentials Application Default Credentials},
    *     your project ID will be detected automatically.
-   * @param {function} [options.promise] - Custom promise module to use instead
-   *     of native Promises.
    * @param {string} [options.apiEndpoint] - The domain name of the
    *     API remote host.
    */
@@ -92,28 +95,31 @@ export class ClusterControllerClient {
     // If we are in browser, we are already using fallback because of the
     // "browser" field in package.json.
     // But if we were explicitly requested to use fallback, let's do it now.
-    const gaxModule = !isBrowser && opts.fallback ? gax.fallback : gax;
+    this._gaxModule = !isBrowser && opts.fallback ? gax.fallback : gax;
 
     // Create a `gaxGrpc` object, with any grpc-specific options
     // sent to the client.
     opts.scopes = (this.constructor as typeof ClusterControllerClient).scopes;
-    const gaxGrpc = new gaxModule.GrpcClient(opts);
+    this._gaxGrpc = new this._gaxModule.GrpcClient(opts);
+
+    // Save options to use in initialize() method.
+    this._opts = opts;
 
     // Save the auth object to the client, for use by other methods.
-    this.auth = (gaxGrpc.auth as gax.GoogleAuth);
+    this.auth = (this._gaxGrpc.auth as gax.GoogleAuth);
 
     // Determine the client header string.
     const clientHeader = [
-      `gax/${gaxModule.version}`,
+      `gax/${this._gaxModule.version}`,
       `gapic/${version}`,
     ];
     if (typeof process !== 'undefined' && 'versions' in process) {
       clientHeader.push(`gl-node/${process.versions.node}`);
     } else {
-      clientHeader.push(`gl-web/${gaxModule.version}`);
+      clientHeader.push(`gl-web/${this._gaxModule.version}`);
     }
     if (!opts.fallback) {
-      clientHeader.push(`grpc/${gaxGrpc.grpcVersion}`);
+      clientHeader.push(`grpc/${this._gaxGrpc.grpcVersion}`);
     }
     if (opts.libName && opts.libVersion) {
       clientHeader.push(`${opts.libName}/${opts.libVersion}`);
@@ -123,7 +129,7 @@ export class ClusterControllerClient {
     // For browsers, pass the JSON content.
 
     const nodejsProtoPath = path.join(__dirname, '..', '..', 'protos', 'protos.json');
-    const protos = gaxGrpc.loadProto(
+    this._protos = this._gaxGrpc.loadProto(
       opts.fallback ?
         require("../../protos/protos.json") :
         nodejsProtoPath
@@ -133,16 +139,16 @@ export class ClusterControllerClient {
     // identifiers to uniquely identify resources within the API.
     // Create useful helper objects for these.
     this._pathTemplates = {
-      projectLocationAutoscalingPolicyPathTemplate: new gaxModule.PathTemplate(
+      projectLocationAutoscalingPolicyPathTemplate: new this._gaxModule.PathTemplate(
         'projects/{project}/locations/{location}/autoscalingPolicies/{autoscaling_policy}'
       ),
-      projectLocationWorkflowTemplatePathTemplate: new gaxModule.PathTemplate(
+      projectLocationWorkflowTemplatePathTemplate: new this._gaxModule.PathTemplate(
         'projects/{project}/locations/{location}/workflowTemplates/{workflow_template}'
       ),
-      projectRegionAutoscalingPolicyPathTemplate: new gaxModule.PathTemplate(
+      projectRegionAutoscalingPolicyPathTemplate: new this._gaxModule.PathTemplate(
         'projects/{project}/regions/{region}/autoscalingPolicies/{autoscaling_policy}'
       ),
-      projectRegionWorkflowTemplatePathTemplate: new gaxModule.PathTemplate(
+      projectRegionWorkflowTemplatePathTemplate: new this._gaxModule.PathTemplate(
         'projects/{project}/regions/{region}/workflowTemplates/{workflow_template}'
       ),
     };
@@ -152,19 +158,19 @@ export class ClusterControllerClient {
     // pages). Denote the keys used for pagination and results.
     this._descriptors.page = {
       listClusters:
-          new gaxModule.PageDescriptor('pageToken', 'nextPageToken', 'clusters')
+          new this._gaxModule.PageDescriptor('pageToken', 'nextPageToken', 'clusters')
     };
 
     // This API contains "long-running operations", which return a
     // an Operation object that allows for tracking of the operation,
     // rather than holding a request open.
     const protoFilesRoot = opts.fallback?
-      gaxModule.protobuf.Root.fromJSON(require("../../protos/protos.json")) :
-      gaxModule.protobuf.loadSync(nodejsProtoPath);
+      this._gaxModule.protobuf.Root.fromJSON(require("../../protos/protos.json")) :
+      this._gaxModule.protobuf.loadSync(nodejsProtoPath);
 
-    this.operationsClient = gaxModule.lro({
+    this.operationsClient = this._gaxModule.lro({
       auth: this.auth,
-      grpc: 'grpc' in gaxGrpc ? gaxGrpc.grpc : undefined
+      grpc: 'grpc' in this._gaxGrpc ? this._gaxGrpc.grpc : undefined
     }).operationsClient(opts);
     const createClusterResponse = protoFilesRoot.lookup(
       '.google.cloud.dataproc.v1.Cluster') as gax.protobuf.Type;
@@ -184,26 +190,26 @@ export class ClusterControllerClient {
       '.google.cloud.dataproc.v1.DiagnoseClusterResults') as gax.protobuf.Type;
 
     this._descriptors.longrunning = {
-      createCluster: new gaxModule.LongrunningDescriptor(
+      createCluster: new this._gaxModule.LongrunningDescriptor(
         this.operationsClient,
         createClusterResponse.decode.bind(createClusterResponse),
         createClusterMetadata.decode.bind(createClusterMetadata)),
-      updateCluster: new gaxModule.LongrunningDescriptor(
+      updateCluster: new this._gaxModule.LongrunningDescriptor(
         this.operationsClient,
         updateClusterResponse.decode.bind(updateClusterResponse),
         updateClusterMetadata.decode.bind(updateClusterMetadata)),
-      deleteCluster: new gaxModule.LongrunningDescriptor(
+      deleteCluster: new this._gaxModule.LongrunningDescriptor(
         this.operationsClient,
         deleteClusterResponse.decode.bind(deleteClusterResponse),
         deleteClusterMetadata.decode.bind(deleteClusterMetadata)),
-      diagnoseCluster: new gaxModule.LongrunningDescriptor(
+      diagnoseCluster: new this._gaxModule.LongrunningDescriptor(
         this.operationsClient,
         diagnoseClusterResponse.decode.bind(diagnoseClusterResponse),
         diagnoseClusterMetadata.decode.bind(diagnoseClusterMetadata))
     };
 
     // Put together the default options sent with requests.
-    const defaults = gaxGrpc.constructSettings(
+    this._defaults = this._gaxGrpc.constructSettings(
         'google.cloud.dataproc.v1.ClusterController', gapicConfig as gax.ClientConfig,
         opts.clientConfig || {}, {'x-goog-api-client': clientHeader.join(' ')});
 
@@ -211,15 +217,33 @@ export class ClusterControllerClient {
     // of calling the API is handled in `google-gax`, with this code
     // merely providing the destination and request information.
     this._innerApiCalls = {};
+  }
+
+  /**
+   * Initialize the client.
+   * Performs asynchronous operations (such as authentication) and prepares the client.
+   * This function will be called automatically when any class method is called for the
+   * first time, but if you need to initialize it before calling an actual method,
+   * feel free to call initialize() directly.
+   *
+   * You can await on this method if you want to make sure the client is initialized.
+   *
+   * @returns {Promise} A promise that resolves to an authenticated service stub.
+   */
+  initialize() {
+    // If the client stub promise is already initialized, return immediately.
+    if (this.clusterControllerStub) {
+      return this.clusterControllerStub;
+    }
 
     // Put together the "service stub" for
     // google.cloud.dataproc.v1.ClusterController.
-    this.clusterControllerStub = gaxGrpc.createStub(
-        opts.fallback ?
-          (protos as protobuf.Root).lookupService('google.cloud.dataproc.v1.ClusterController') :
+    this.clusterControllerStub = this._gaxGrpc.createStub(
+        this._opts.fallback ?
+          (this._protos as protobuf.Root).lookupService('google.cloud.dataproc.v1.ClusterController') :
           // tslint:disable-next-line no-any
-          (protos as any).google.cloud.dataproc.v1.ClusterController,
-        opts) as Promise<{[method: string]: Function}>;
+          (this._protos as any).google.cloud.dataproc.v1.ClusterController,
+        this._opts) as Promise<{[method: string]: Function}>;
 
     // Iterate over each of the methods that the service provides
     // and create an API call method for each.
@@ -238,9 +262,9 @@ export class ClusterControllerClient {
           throw err;
         });
 
-      const apiCall = gaxModule.createApiCall(
+      const apiCall = this._gaxModule.createApiCall(
         innerCallPromise,
-        defaults[methodName],
+        this._defaults[methodName],
         this._descriptors.page[methodName] ||
             this._descriptors.stream[methodName] ||
             this._descriptors.longrunning[methodName]
@@ -254,6 +278,8 @@ export class ClusterControllerClient {
         return apiCall(argument, callOptions, callback);
       };
     }
+
+    return this.clusterControllerStub;
   }
 
   /**
@@ -362,6 +388,7 @@ export class ClusterControllerClient {
       options = optionsOrCallback as gax.CallOptions;
     }
     options = options || {};
+    this.initialize();
     return this._innerApiCalls.getCluster(request, options, callback);
   }
 
@@ -381,7 +408,7 @@ export class ClusterControllerClient {
           {}|undefined>): void;
 /**
  * Creates a cluster in a project. The returned
- * [Operation.metadata][google.longrunning.Operation.metadata] will be
+ * {@link google.longrunning.Operation.metadata|Operation.metadata} will be
  * [ClusterOperationMetadata](https://cloud.google.com/dataproc/docs/reference/rpc/google.cloud.dataproc.v1#clusteroperationmetadata).
  *
  * @param {Object} request
@@ -395,9 +422,9 @@ export class ClusterControllerClient {
  *   Required. The cluster to create.
  * @param {string} [request.requestId]
  *   Optional. A unique id used to identify the request. If the server
- *   receives two [CreateClusterRequest][google.cloud.dataproc.v1.CreateClusterRequest] requests  with the same
+ *   receives two {@link google.cloud.dataproc.v1.CreateClusterRequest|CreateClusterRequest} requests  with the same
  *   id, then the second request will be ignored and the
- *   first [google.longrunning.Operation][google.longrunning.Operation] created and stored in the backend
+ *   first {@link google.longrunning.Operation|google.longrunning.Operation} created and stored in the backend
  *   is returned.
  *
  *   It is recommended to always set this value to a
@@ -434,6 +461,7 @@ export class ClusterControllerClient {
       options = optionsOrCallback as gax.CallOptions;
     }
     options = options || {};
+    this.initialize();
     return this._innerApiCalls.createCluster(request, options, callback);
   }
   updateCluster(
@@ -452,7 +480,7 @@ export class ClusterControllerClient {
           {}|undefined>): void;
 /**
  * Updates a cluster in a project. The returned
- * [Operation.metadata][google.longrunning.Operation.metadata] will be
+ * {@link google.longrunning.Operation.metadata|Operation.metadata} will be
  * [ClusterOperationMetadata](https://cloud.google.com/dataproc/docs/reference/rpc/google.cloud.dataproc.v1#clusteroperationmetadata).
  *
  * @param {Object} request
@@ -530,9 +558,9 @@ export class ClusterControllerClient {
  *    </table>
  * @param {string} [request.requestId]
  *   Optional. A unique id used to identify the request. If the server
- *   receives two [UpdateClusterRequest][google.cloud.dataproc.v1.UpdateClusterRequest] requests  with the same
+ *   receives two {@link google.cloud.dataproc.v1.UpdateClusterRequest|UpdateClusterRequest} requests  with the same
  *   id, then the second request will be ignored and the
- *   first [google.longrunning.Operation][google.longrunning.Operation] created and stored in the
+ *   first {@link google.longrunning.Operation|google.longrunning.Operation} created and stored in the
  *   backend is returned.
  *
  *   It is recommended to always set this value to a
@@ -569,6 +597,7 @@ export class ClusterControllerClient {
       options = optionsOrCallback as gax.CallOptions;
     }
     options = options || {};
+    this.initialize();
     return this._innerApiCalls.updateCluster(request, options, callback);
   }
   deleteCluster(
@@ -587,7 +616,7 @@ export class ClusterControllerClient {
           {}|undefined>): void;
 /**
  * Deletes a cluster in a project. The returned
- * [Operation.metadata][google.longrunning.Operation.metadata] will be
+ * {@link google.longrunning.Operation.metadata|Operation.metadata} will be
  * [ClusterOperationMetadata](https://cloud.google.com/dataproc/docs/reference/rpc/google.cloud.dataproc.v1#clusteroperationmetadata).
  *
  * @param {Object} request
@@ -604,9 +633,9 @@ export class ClusterControllerClient {
  *   (with error NOT_FOUND) if cluster with specified UUID does not exist.
  * @param {string} [request.requestId]
  *   Optional. A unique id used to identify the request. If the server
- *   receives two [DeleteClusterRequest][google.cloud.dataproc.v1.DeleteClusterRequest] requests  with the same
+ *   receives two {@link google.cloud.dataproc.v1.DeleteClusterRequest|DeleteClusterRequest} requests  with the same
  *   id, then the second request will be ignored and the
- *   first [google.longrunning.Operation][google.longrunning.Operation] created and stored in the
+ *   first {@link google.longrunning.Operation|google.longrunning.Operation} created and stored in the
  *   backend is returned.
  *
  *   It is recommended to always set this value to a
@@ -643,6 +672,7 @@ export class ClusterControllerClient {
       options = optionsOrCallback as gax.CallOptions;
     }
     options = options || {};
+    this.initialize();
     return this._innerApiCalls.deleteCluster(request, options, callback);
   }
   diagnoseCluster(
@@ -661,10 +691,10 @@ export class ClusterControllerClient {
           {}|undefined>): void;
 /**
  * Gets cluster diagnostic information. The returned
- * [Operation.metadata][google.longrunning.Operation.metadata] will be
+ * {@link google.longrunning.Operation.metadata|Operation.metadata} will be
  * [ClusterOperationMetadata](https://cloud.google.com/dataproc/docs/reference/rpc/google.cloud.dataproc.v1#clusteroperationmetadata).
  * After the operation completes,
- * [Operation.response][google.longrunning.Operation.response]
+ * {@link google.longrunning.Operation.response|Operation.response}
  * contains
  * [DiagnoseClusterResults](https://cloud.google.com/dataproc/docs/reference/rpc/google.cloud.dataproc.v1#diagnoseclusterresults).
  *
@@ -706,6 +736,7 @@ export class ClusterControllerClient {
       options = optionsOrCallback as gax.CallOptions;
     }
     options = options || {};
+    this.initialize();
     return this._innerApiCalls.diagnoseCluster(request, options, callback);
   }
   listClusters(
@@ -800,6 +831,7 @@ export class ClusterControllerClient {
       options = optionsOrCallback as gax.CallOptions;
     }
     options = options || {};
+    this.initialize();
     return this._innerApiCalls.listClusters(request, options, callback);
   }
 
@@ -859,6 +891,7 @@ export class ClusterControllerClient {
     request = request || {};
     options = options || {};
     const callSettings = new gax.CallSettings(options);
+    this.initialize();
     return this._descriptors.page.listClusters.createStream(
       this._innerApiCalls.listClusters as gax.GaxCall,
       request,
@@ -1071,8 +1104,9 @@ export class ClusterControllerClient {
    * The client will no longer be usable and all future behavior is undefined.
    */
   close(): Promise<void> {
+    this.initialize();
     if (!this._terminated) {
-      return this.clusterControllerStub.then(stub => {
+      return this.clusterControllerStub!.then(stub => {
         this._terminated = true;
         stub.close();
       });
diff --git a/packages/google-cloud-dataproc/src/v1/job_controller_client.ts b/packages/google-cloud-dataproc/src/v1/job_controller_client.ts
index b8fbfdaa87a..b2da8faa6a0 100644
--- a/packages/google-cloud-dataproc/src/v1/job_controller_client.ts
+++ b/packages/google-cloud-dataproc/src/v1/job_controller_client.ts
@@ -36,8 +36,13 @@ export class JobControllerClient {
   private _innerApiCalls: {[name: string]: Function};
   private _pathTemplates: {[name: string]: gax.PathTemplate};
   private _terminated = false;
+  private _opts: ClientOptions;
+  private _gaxModule: typeof gax | typeof gax.fallback;
+  private _gaxGrpc: gax.GrpcClient | gax.fallback.GrpcClient;
+  private _protos: {};
+  private _defaults: {[method: string]: gax.CallSettings};
   auth: gax.GoogleAuth;
-  jobControllerStub: Promise<{[name: string]: Function}>;
+  jobControllerStub?: Promise<{[name: string]: Function}>;
 
   /**
    * Construct an instance of JobControllerClient.
@@ -61,8 +66,6 @@ export class JobControllerClient {
    *     app is running in an environment which supports
    *     {@link https://developers.google.com/identity/protocols/application-default-credentials Application Default Credentials},
    *     your project ID will be detected automatically.
-   * @param {function} [options.promise] - Custom promise module to use instead
-   *     of native Promises.
    * @param {string} [options.apiEndpoint] - The domain name of the
    *     API remote host.
    */
@@ -90,28 +93,31 @@ export class JobControllerClient {
     // If we are in browser, we are already using fallback because of the
     // "browser" field in package.json.
     // But if we were explicitly requested to use fallback, let's do it now.
-    const gaxModule = !isBrowser && opts.fallback ? gax.fallback : gax;
+    this._gaxModule = !isBrowser && opts.fallback ? gax.fallback : gax;
 
     // Create a `gaxGrpc` object, with any grpc-specific options
     // sent to the client.
     opts.scopes = (this.constructor as typeof JobControllerClient).scopes;
-    const gaxGrpc = new gaxModule.GrpcClient(opts);
+    this._gaxGrpc = new this._gaxModule.GrpcClient(opts);
+
+    // Save options to use in initialize() method.
+    this._opts = opts;
 
     // Save the auth object to the client, for use by other methods.
-    this.auth = (gaxGrpc.auth as gax.GoogleAuth);
+    this.auth = (this._gaxGrpc.auth as gax.GoogleAuth);
 
     // Determine the client header string.
     const clientHeader = [
-      `gax/${gaxModule.version}`,
+      `gax/${this._gaxModule.version}`,
       `gapic/${version}`,
     ];
     if (typeof process !== 'undefined' && 'versions' in process) {
       clientHeader.push(`gl-node/${process.versions.node}`);
     } else {
-      clientHeader.push(`gl-web/${gaxModule.version}`);
+      clientHeader.push(`gl-web/${this._gaxModule.version}`);
     }
     if (!opts.fallback) {
-      clientHeader.push(`grpc/${gaxGrpc.grpcVersion}`);
+      clientHeader.push(`grpc/${this._gaxGrpc.grpcVersion}`);
     }
     if (opts.libName && opts.libVersion) {
       clientHeader.push(`${opts.libName}/${opts.libVersion}`);
@@ -121,7 +127,7 @@ export class JobControllerClient {
     // For browsers, pass the JSON content.
 
     const nodejsProtoPath = path.join(__dirname, '..', '..', 'protos', 'protos.json');
-    const protos = gaxGrpc.loadProto(
+    this._protos = this._gaxGrpc.loadProto(
       opts.fallback ?
         require("../../protos/protos.json") :
         nodejsProtoPath
@@ -131,16 +137,16 @@ export class JobControllerClient {
     // identifiers to uniquely identify resources within the API.
     // Create useful helper objects for these.
     this._pathTemplates = {
-      projectLocationAutoscalingPolicyPathTemplate: new gaxModule.PathTemplate(
+      projectLocationAutoscalingPolicyPathTemplate: new this._gaxModule.PathTemplate(
         'projects/{project}/locations/{location}/autoscalingPolicies/{autoscaling_policy}'
       ),
-      projectLocationWorkflowTemplatePathTemplate: new gaxModule.PathTemplate(
+      projectLocationWorkflowTemplatePathTemplate: new this._gaxModule.PathTemplate(
         'projects/{project}/locations/{location}/workflowTemplates/{workflow_template}'
       ),
-      projectRegionAutoscalingPolicyPathTemplate: new gaxModule.PathTemplate(
+      projectRegionAutoscalingPolicyPathTemplate: new this._gaxModule.PathTemplate(
         'projects/{project}/regions/{region}/autoscalingPolicies/{autoscaling_policy}'
       ),
-      projectRegionWorkflowTemplatePathTemplate: new gaxModule.PathTemplate(
+      projectRegionWorkflowTemplatePathTemplate: new this._gaxModule.PathTemplate(
         'projects/{project}/regions/{region}/workflowTemplates/{workflow_template}'
       ),
     };
@@ -150,11 +156,11 @@ export class JobControllerClient {
     // pages). Denote the keys used for pagination and results.
     this._descriptors.page = {
       listJobs:
-          new gaxModule.PageDescriptor('pageToken', 'nextPageToken', 'jobs')
+          new this._gaxModule.PageDescriptor('pageToken', 'nextPageToken', 'jobs')
     };
 
     // Put together the default options sent with requests.
-    const defaults = gaxGrpc.constructSettings(
+    this._defaults = this._gaxGrpc.constructSettings(
         'google.cloud.dataproc.v1.JobController', gapicConfig as gax.ClientConfig,
         opts.clientConfig || {}, {'x-goog-api-client': clientHeader.join(' ')});
 
@@ -162,15 +168,33 @@ export class JobControllerClient {
     // of calling the API is handled in `google-gax`, with this code
     // merely providing the destination and request information.
     this._innerApiCalls = {};
+  }
+
+  /**
+   * Initialize the client.
+   * Performs asynchronous operations (such as authentication) and prepares the client.
+   * This function will be called automatically when any class method is called for the
+   * first time, but if you need to initialize it before calling an actual method,
+   * feel free to call initialize() directly.
+   *
+   * You can await on this method if you want to make sure the client is initialized.
+   *
+   * @returns {Promise} A promise that resolves to an authenticated service stub.
+   */
+  initialize() {
+    // If the client stub promise is already initialized, return immediately.
+    if (this.jobControllerStub) {
+      return this.jobControllerStub;
+    }
 
     // Put together the "service stub" for
     // google.cloud.dataproc.v1.JobController.
-    this.jobControllerStub = gaxGrpc.createStub(
-        opts.fallback ?
-          (protos as protobuf.Root).lookupService('google.cloud.dataproc.v1.JobController') :
+    this.jobControllerStub = this._gaxGrpc.createStub(
+        this._opts.fallback ?
+          (this._protos as protobuf.Root).lookupService('google.cloud.dataproc.v1.JobController') :
           // tslint:disable-next-line no-any
-          (protos as any).google.cloud.dataproc.v1.JobController,
-        opts) as Promise<{[method: string]: Function}>;
+          (this._protos as any).google.cloud.dataproc.v1.JobController,
+        this._opts) as Promise<{[method: string]: Function}>;
 
     // Iterate over each of the methods that the service provides
     // and create an API call method for each.
@@ -189,9 +213,9 @@ export class JobControllerClient {
           throw err;
         });
 
-      const apiCall = gaxModule.createApiCall(
+      const apiCall = this._gaxModule.createApiCall(
         innerCallPromise,
-        defaults[methodName],
+        this._defaults[methodName],
         this._descriptors.page[methodName] ||
             this._descriptors.stream[methodName] ||
             this._descriptors.longrunning[methodName]
@@ -205,6 +229,8 @@ export class JobControllerClient {
         return apiCall(argument, callOptions, callback);
       };
     }
+
+    return this.jobControllerStub;
   }
 
   /**
@@ -286,9 +312,9 @@ export class JobControllerClient {
  *   Required. The job resource.
  * @param {string} [request.requestId]
  *   Optional. A unique id used to identify the request. If the server
- *   receives two [SubmitJobRequest][google.cloud.dataproc.v1.SubmitJobRequest] requests  with the same
+ *   receives two {@link google.cloud.dataproc.v1.SubmitJobRequest|SubmitJobRequest} requests  with the same
  *   id, then the second request will be ignored and the
- *   first [Job][google.cloud.dataproc.v1.Job] created and stored in the backend
+ *   first {@link google.cloud.dataproc.v1.Job|Job} created and stored in the backend
  *   is returned.
  *
  *   It is recommended to always set this value to a
@@ -325,6 +351,7 @@ export class JobControllerClient {
       options = optionsOrCallback as gax.CallOptions;
     }
     options = options || {};
+    this.initialize();
     return this._innerApiCalls.submitJob(request, options, callback);
   }
   getJob(
@@ -382,6 +409,7 @@ export class JobControllerClient {
       options = optionsOrCallback as gax.CallOptions;
     }
     options = options || {};
+    this.initialize();
     return this._innerApiCalls.getJob(request, options, callback);
   }
   updateJob(
@@ -448,6 +476,7 @@ export class JobControllerClient {
       options = optionsOrCallback as gax.CallOptions;
     }
     options = options || {};
+    this.initialize();
     return this._innerApiCalls.updateJob(request, options, callback);
   }
   cancelJob(
@@ -509,6 +538,7 @@ export class JobControllerClient {
       options = optionsOrCallback as gax.CallOptions;
     }
     options = options || {};
+    this.initialize();
     return this._innerApiCalls.cancelJob(request, options, callback);
   }
   deleteJob(
@@ -567,6 +597,7 @@ export class JobControllerClient {
       options = optionsOrCallback as gax.CallOptions;
     }
     options = options || {};
+    this.initialize();
     return this._innerApiCalls.deleteJob(request, options, callback);
   }
 
@@ -666,6 +697,7 @@ export class JobControllerClient {
       options = optionsOrCallback as gax.CallOptions;
     }
     options = options || {};
+    this.initialize();
     return this._innerApiCalls.listJobs(request, options, callback);
   }
 
@@ -729,6 +761,7 @@ export class JobControllerClient {
     request = request || {};
     options = options || {};
     const callSettings = new gax.CallSettings(options);
+    this.initialize();
     return this._descriptors.page.listJobs.createStream(
       this._innerApiCalls.listJobs as gax.GaxCall,
       request,
@@ -941,8 +974,9 @@ export class JobControllerClient {
    * The client will no longer be usable and all future behavior is undefined.
    */
   close(): Promise<void> {
+    this.initialize();
     if (!this._terminated) {
-      return this.jobControllerStub.then(stub => {
+      return this.jobControllerStub!.then(stub => {
         this._terminated = true;
         stub.close();
       });
diff --git a/packages/google-cloud-dataproc/src/v1/workflow_template_service_client.ts b/packages/google-cloud-dataproc/src/v1/workflow_template_service_client.ts
index b65c1fc95de..641f83baf20 100644
--- a/packages/google-cloud-dataproc/src/v1/workflow_template_service_client.ts
+++ b/packages/google-cloud-dataproc/src/v1/workflow_template_service_client.ts
@@ -37,9 +37,14 @@ export class WorkflowTemplateServiceClient {
   private _innerApiCalls: {[name: string]: Function};
   private _pathTemplates: {[name: string]: gax.PathTemplate};
   private _terminated = false;
+  private _opts: ClientOptions;
+  private _gaxModule: typeof gax | typeof gax.fallback;
+  private _gaxGrpc: gax.GrpcClient | gax.fallback.GrpcClient;
+  private _protos: {};
+  private _defaults: {[method: string]: gax.CallSettings};
   auth: gax.GoogleAuth;
   operationsClient: gax.OperationsClient;
-  workflowTemplateServiceStub: Promise<{[name: string]: Function}>;
+  workflowTemplateServiceStub?: Promise<{[name: string]: Function}>;
 
   /**
    * Construct an instance of WorkflowTemplateServiceClient.
@@ -63,8 +68,6 @@ export class WorkflowTemplateServiceClient {
    *     app is running in an environment which supports
    *     {@link https://developers.google.com/identity/protocols/application-default-credentials Application Default Credentials},
    *     your project ID will be detected automatically.
-   * @param {function} [options.promise] - Custom promise module to use instead
-   *     of native Promises.
    * @param {string} [options.apiEndpoint] - The domain name of the
    *     API remote host.
    */
@@ -92,28 +95,31 @@ export class WorkflowTemplateServiceClient {
     // If we are in browser, we are already using fallback because of the
     // "browser" field in package.json.
     // But if we were explicitly requested to use fallback, let's do it now.
-    const gaxModule = !isBrowser && opts.fallback ? gax.fallback : gax;
+    this._gaxModule = !isBrowser && opts.fallback ? gax.fallback : gax;
 
     // Create a `gaxGrpc` object, with any grpc-specific options
     // sent to the client.
     opts.scopes = (this.constructor as typeof WorkflowTemplateServiceClient).scopes;
-    const gaxGrpc = new gaxModule.GrpcClient(opts);
+    this._gaxGrpc = new this._gaxModule.GrpcClient(opts);
+
+    // Save options to use in initialize() method.
+    this._opts = opts;
 
     // Save the auth object to the client, for use by other methods.
-    this.auth = (gaxGrpc.auth as gax.GoogleAuth);
+    this.auth = (this._gaxGrpc.auth as gax.GoogleAuth);
 
     // Determine the client header string.
     const clientHeader = [
-      `gax/${gaxModule.version}`,
+      `gax/${this._gaxModule.version}`,
       `gapic/${version}`,
     ];
     if (typeof process !== 'undefined' && 'versions' in process) {
       clientHeader.push(`gl-node/${process.versions.node}`);
     } else {
-      clientHeader.push(`gl-web/${gaxModule.version}`);
+      clientHeader.push(`gl-web/${this._gaxModule.version}`);
     }
     if (!opts.fallback) {
-      clientHeader.push(`grpc/${gaxGrpc.grpcVersion}`);
+      clientHeader.push(`grpc/${this._gaxGrpc.grpcVersion}`);
     }
     if (opts.libName && opts.libVersion) {
       clientHeader.push(`${opts.libName}/${opts.libVersion}`);
@@ -123,7 +129,7 @@ export class WorkflowTemplateServiceClient {
     // For browsers, pass the JSON content.
 
     const nodejsProtoPath = path.join(__dirname, '..', '..', 'protos', 'protos.json');
-    const protos = gaxGrpc.loadProto(
+    this._protos = this._gaxGrpc.loadProto(
       opts.fallback ?
         require("../../protos/protos.json") :
         nodejsProtoPath
@@ -133,19 +139,19 @@ export class WorkflowTemplateServiceClient {
     // identifiers to uniquely identify resources within the API.
     // Create useful helper objects for these.
     this._pathTemplates = {
-      projectLocationAutoscalingPolicyPathTemplate: new gaxModule.PathTemplate(
+      projectLocationAutoscalingPolicyPathTemplate: new this._gaxModule.PathTemplate(
         'projects/{project}/locations/{location}/autoscalingPolicies/{autoscaling_policy}'
       ),
-      projectLocationWorkflowTemplatePathTemplate: new gaxModule.PathTemplate(
+      projectLocationWorkflowTemplatePathTemplate: new this._gaxModule.PathTemplate(
         'projects/{project}/locations/{location}/workflowTemplates/{workflow_template}'
       ),
-      projectRegionAutoscalingPolicyPathTemplate: new gaxModule.PathTemplate(
+      projectRegionAutoscalingPolicyPathTemplate: new this._gaxModule.PathTemplate(
         'projects/{project}/regions/{region}/autoscalingPolicies/{autoscaling_policy}'
       ),
-      projectRegionWorkflowTemplatePathTemplate: new gaxModule.PathTemplate(
+      projectRegionWorkflowTemplatePathTemplate: new this._gaxModule.PathTemplate(
         'projects/{project}/regions/{region}/workflowTemplates/{workflow_template}'
       ),
-      regionPathTemplate: new gaxModule.PathTemplate(
+      regionPathTemplate: new this._gaxModule.PathTemplate(
         'projects/{project}/regions/{region}'
       ),
     };
@@ -155,19 +161,19 @@ export class WorkflowTemplateServiceClient {
     // pages). Denote the keys used for pagination and results.
     this._descriptors.page = {
       listWorkflowTemplates:
-          new gaxModule.PageDescriptor('pageToken', 'nextPageToken', 'templates')
+          new this._gaxModule.PageDescriptor('pageToken', 'nextPageToken', 'templates')
     };
 
     // This API contains "long-running operations", which return a
     // an Operation object that allows for tracking of the operation,
     // rather than holding a request open.
     const protoFilesRoot = opts.fallback?
-      gaxModule.protobuf.Root.fromJSON(require("../../protos/protos.json")) :
-      gaxModule.protobuf.loadSync(nodejsProtoPath);
+      this._gaxModule.protobuf.Root.fromJSON(require("../../protos/protos.json")) :
+      this._gaxModule.protobuf.loadSync(nodejsProtoPath);
 
-    this.operationsClient = gaxModule.lro({
+    this.operationsClient = this._gaxModule.lro({
       auth: this.auth,
-      grpc: 'grpc' in gaxGrpc ? gaxGrpc.grpc : undefined
+      grpc: 'grpc' in this._gaxGrpc ? this._gaxGrpc.grpc : undefined
     }).operationsClient(opts);
     const instantiateWorkflowTemplateResponse = protoFilesRoot.lookup(
       '.google.protobuf.Empty') as gax.protobuf.Type;
@@ -179,18 +185,18 @@ export class WorkflowTemplateServiceClient {
       '.google.cloud.dataproc.v1.WorkflowMetadata') as gax.protobuf.Type;
 
     this._descriptors.longrunning = {
-      instantiateWorkflowTemplate: new gaxModule.LongrunningDescriptor(
+      instantiateWorkflowTemplate: new this._gaxModule.LongrunningDescriptor(
         this.operationsClient,
         instantiateWorkflowTemplateResponse.decode.bind(instantiateWorkflowTemplateResponse),
         instantiateWorkflowTemplateMetadata.decode.bind(instantiateWorkflowTemplateMetadata)),
-      instantiateInlineWorkflowTemplate: new gaxModule.LongrunningDescriptor(
+      instantiateInlineWorkflowTemplate: new this._gaxModule.LongrunningDescriptor(
         this.operationsClient,
         instantiateInlineWorkflowTemplateResponse.decode.bind(instantiateInlineWorkflowTemplateResponse),
         instantiateInlineWorkflowTemplateMetadata.decode.bind(instantiateInlineWorkflowTemplateMetadata))
     };
 
     // Put together the default options sent with requests.
-    const defaults = gaxGrpc.constructSettings(
+    this._defaults = this._gaxGrpc.constructSettings(
         'google.cloud.dataproc.v1.WorkflowTemplateService', gapicConfig as gax.ClientConfig,
         opts.clientConfig || {}, {'x-goog-api-client': clientHeader.join(' ')});
 
@@ -198,15 +204,33 @@ export class WorkflowTemplateServiceClient {
     // of calling the API is handled in `google-gax`, with this code
     // merely providing the destination and request information.
     this._innerApiCalls = {};
+  }
+
+  /**
+   * Initialize the client.
+   * Performs asynchronous operations (such as authentication) and prepares the client.
+   * This function will be called automatically when any class method is called for the
+   * first time, but if you need to initialize it before calling an actual method,
+   * feel free to call initialize() directly.
+   *
+   * You can await on this method if you want to make sure the client is initialized.
+   *
+   * @returns {Promise} A promise that resolves to an authenticated service stub.
+   */
+  initialize() {
+    // If the client stub promise is already initialized, return immediately.
+    if (this.workflowTemplateServiceStub) {
+      return this.workflowTemplateServiceStub;
+    }
 
     // Put together the "service stub" for
     // google.cloud.dataproc.v1.WorkflowTemplateService.
-    this.workflowTemplateServiceStub = gaxGrpc.createStub(
-        opts.fallback ?
-          (protos as protobuf.Root).lookupService('google.cloud.dataproc.v1.WorkflowTemplateService') :
+    this.workflowTemplateServiceStub = this._gaxGrpc.createStub(
+        this._opts.fallback ?
+          (this._protos as protobuf.Root).lookupService('google.cloud.dataproc.v1.WorkflowTemplateService') :
           // tslint:disable-next-line no-any
-          (protos as any).google.cloud.dataproc.v1.WorkflowTemplateService,
-        opts) as Promise<{[method: string]: Function}>;
+          (this._protos as any).google.cloud.dataproc.v1.WorkflowTemplateService,
+        this._opts) as Promise<{[method: string]: Function}>;
 
     // Iterate over each of the methods that the service provides
     // and create an API call method for each.
@@ -225,9 +249,9 @@ export class WorkflowTemplateServiceClient {
           throw err;
         });
 
-      const apiCall = gaxModule.createApiCall(
+      const apiCall = this._gaxModule.createApiCall(
         innerCallPromise,
-        defaults[methodName],
+        this._defaults[methodName],
         this._descriptors.page[methodName] ||
             this._descriptors.stream[methodName] ||
             this._descriptors.longrunning[methodName]
@@ -241,6 +265,8 @@ export class WorkflowTemplateServiceClient {
         return apiCall(argument, callOptions, callback);
       };
     }
+
+    return this.workflowTemplateServiceStub;
   }
 
   /**
@@ -362,6 +388,7 @@ export class WorkflowTemplateServiceClient {
     ] = gax.routingHeader.fromParams({
       'parent': request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.createWorkflowTemplate(request, options, callback);
   }
   getWorkflowTemplate(
@@ -438,6 +465,7 @@ export class WorkflowTemplateServiceClient {
     ] = gax.routingHeader.fromParams({
       'name': request.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.getWorkflowTemplate(request, options, callback);
   }
   updateWorkflowTemplate(
@@ -500,6 +528,7 @@ export class WorkflowTemplateServiceClient {
     ] = gax.routingHeader.fromParams({
       'template.name': request.template!.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.updateWorkflowTemplate(request, options, callback);
   }
   deleteWorkflowTemplate(
@@ -572,6 +601,7 @@ export class WorkflowTemplateServiceClient {
     ] = gax.routingHeader.fromParams({
       'name': request.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.deleteWorkflowTemplate(request, options, callback);
   }
 
@@ -594,22 +624,22 @@ export class WorkflowTemplateServiceClient {
  *
  * The returned Operation can be used to track execution of
  * workflow by polling
- * [operations.get][google.longrunning.Operations.GetOperation].
+ * {@link google.longrunning.Operations.GetOperation|operations.get}.
  * The Operation will complete when entire workflow is finished.
  *
  * The running workflow can be aborted via
- * [operations.cancel][google.longrunning.Operations.CancelOperation].
+ * {@link google.longrunning.Operations.CancelOperation|operations.cancel}.
  * This will cause any inflight jobs to be cancelled and workflow-owned
  * clusters to be deleted.
  *
- * The [Operation.metadata][google.longrunning.Operation.metadata] will be
+ * The {@link google.longrunning.Operation.metadata|Operation.metadata} will be
  * [WorkflowMetadata](https://cloud.google.com/dataproc/docs/reference/rpc/google.cloud.dataproc.v1#workflowmetadata).
  * Also see [Using
  * WorkflowMetadata](https://cloud.google.com/dataproc/docs/concepts/workflows/debugging#using_workflowmetadata).
  *
  * On successful completion,
- * [Operation.response][google.longrunning.Operation.response] will be
- * [Empty][google.protobuf.Empty].
+ * {@link google.longrunning.Operation.response|Operation.response} will be
+ * {@link google.protobuf.Empty|Empty}.
  *
  * @param {Object} request
  *   The request object that will be sent.
@@ -680,6 +710,7 @@ export class WorkflowTemplateServiceClient {
     ] = gax.routingHeader.fromParams({
       'name': request.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.instantiateWorkflowTemplate(request, options, callback);
   }
   instantiateInlineWorkflowTemplate(
@@ -700,27 +731,27 @@ export class WorkflowTemplateServiceClient {
  * Instantiates a template and begins execution.
  *
  * This method is equivalent to executing the sequence
- * [CreateWorkflowTemplate][google.cloud.dataproc.v1.WorkflowTemplateService.CreateWorkflowTemplate], [InstantiateWorkflowTemplate][google.cloud.dataproc.v1.WorkflowTemplateService.InstantiateWorkflowTemplate],
- * [DeleteWorkflowTemplate][google.cloud.dataproc.v1.WorkflowTemplateService.DeleteWorkflowTemplate].
+ * {@link google.cloud.dataproc.v1.WorkflowTemplateService.CreateWorkflowTemplate|CreateWorkflowTemplate}, {@link google.cloud.dataproc.v1.WorkflowTemplateService.InstantiateWorkflowTemplate|InstantiateWorkflowTemplate},
+ * {@link google.cloud.dataproc.v1.WorkflowTemplateService.DeleteWorkflowTemplate|DeleteWorkflowTemplate}.
  *
  * The returned Operation can be used to track execution of
  * workflow by polling
- * [operations.get][google.longrunning.Operations.GetOperation].
+ * {@link google.longrunning.Operations.GetOperation|operations.get}.
  * The Operation will complete when entire workflow is finished.
  *
  * The running workflow can be aborted via
- * [operations.cancel][google.longrunning.Operations.CancelOperation].
+ * {@link google.longrunning.Operations.CancelOperation|operations.cancel}.
  * This will cause any inflight jobs to be cancelled and workflow-owned
  * clusters to be deleted.
  *
- * The [Operation.metadata][google.longrunning.Operation.metadata] will be
+ * The {@link google.longrunning.Operation.metadata|Operation.metadata} will be
  * [WorkflowMetadata](https://cloud.google.com/dataproc/docs/reference/rpc/google.cloud.dataproc.v1#workflowmetadata).
  * Also see [Using
  * WorkflowMetadata](https://cloud.google.com/dataproc/docs/concepts/workflows/debugging#using_workflowmetadata).
  *
  * On successful completion,
- * [Operation.response][google.longrunning.Operation.response] will be
- * [Empty][google.protobuf.Empty].
+ * {@link google.longrunning.Operation.response|Operation.response} will be
+ * {@link google.protobuf.Empty|Empty}.
  *
  * @param {Object} request
  *   The request object that will be sent.
@@ -783,6 +814,7 @@ export class WorkflowTemplateServiceClient {
     ] = gax.routingHeader.fromParams({
       'parent': request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.instantiateInlineWorkflowTemplate(request, options, callback);
   }
   listWorkflowTemplates(
@@ -871,6 +903,7 @@ export class WorkflowTemplateServiceClient {
     ] = gax.routingHeader.fromParams({
       'parent': request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.listWorkflowTemplates(request, options, callback);
   }
 
@@ -924,6 +957,7 @@ export class WorkflowTemplateServiceClient {
       'parent': request.parent || '',
     });
     const callSettings = new gax.CallSettings(options);
+    this.initialize();
     return this._descriptors.page.listWorkflowTemplates.createStream(
       this._innerApiCalls.listWorkflowTemplates as gax.GaxCall,
       request,
@@ -1172,8 +1206,9 @@ export class WorkflowTemplateServiceClient {
    * The client will no longer be usable and all future behavior is undefined.
    */
   close(): Promise<void> {
+    this.initialize();
     if (!this._terminated) {
-      return this.workflowTemplateServiceStub.then(stub => {
+      return this.workflowTemplateServiceStub!.then(stub => {
         this._terminated = true;
         stub.close();
       });
diff --git a/packages/google-cloud-dataproc/src/v1beta2/autoscaling_policy_service_client.ts b/packages/google-cloud-dataproc/src/v1beta2/autoscaling_policy_service_client.ts
index 11cdb410c14..c2c619ebf47 100644
--- a/packages/google-cloud-dataproc/src/v1beta2/autoscaling_policy_service_client.ts
+++ b/packages/google-cloud-dataproc/src/v1beta2/autoscaling_policy_service_client.ts
@@ -37,8 +37,13 @@ export class AutoscalingPolicyServiceClient {
   private _innerApiCalls: {[name: string]: Function};
   private _pathTemplates: {[name: string]: gax.PathTemplate};
   private _terminated = false;
+  private _opts: ClientOptions;
+  private _gaxModule: typeof gax | typeof gax.fallback;
+  private _gaxGrpc: gax.GrpcClient | gax.fallback.GrpcClient;
+  private _protos: {};
+  private _defaults: {[method: string]: gax.CallSettings};
   auth: gax.GoogleAuth;
-  autoscalingPolicyServiceStub: Promise<{[name: string]: Function}>;
+  autoscalingPolicyServiceStub?: Promise<{[name: string]: Function}>;
 
   /**
    * Construct an instance of AutoscalingPolicyServiceClient.
@@ -62,8 +67,6 @@ export class AutoscalingPolicyServiceClient {
    *     app is running in an environment which supports
    *     {@link https://developers.google.com/identity/protocols/application-default-credentials Application Default Credentials},
    *     your project ID will be detected automatically.
-   * @param {function} [options.promise] - Custom promise module to use instead
-   *     of native Promises.
    * @param {string} [options.apiEndpoint] - The domain name of the
    *     API remote host.
    */
@@ -91,28 +94,31 @@ export class AutoscalingPolicyServiceClient {
     // If we are in browser, we are already using fallback because of the
     // "browser" field in package.json.
     // But if we were explicitly requested to use fallback, let's do it now.
-    const gaxModule = !isBrowser && opts.fallback ? gax.fallback : gax;
+    this._gaxModule = !isBrowser && opts.fallback ? gax.fallback : gax;
 
     // Create a `gaxGrpc` object, with any grpc-specific options
     // sent to the client.
     opts.scopes = (this.constructor as typeof AutoscalingPolicyServiceClient).scopes;
-    const gaxGrpc = new gaxModule.GrpcClient(opts);
+    this._gaxGrpc = new this._gaxModule.GrpcClient(opts);
+
+    // Save options to use in initialize() method.
+    this._opts = opts;
 
     // Save the auth object to the client, for use by other methods.
-    this.auth = (gaxGrpc.auth as gax.GoogleAuth);
+    this.auth = (this._gaxGrpc.auth as gax.GoogleAuth);
 
     // Determine the client header string.
     const clientHeader = [
-      `gax/${gaxModule.version}`,
+      `gax/${this._gaxModule.version}`,
       `gapic/${version}`,
     ];
     if (typeof process !== 'undefined' && 'versions' in process) {
       clientHeader.push(`gl-node/${process.versions.node}`);
     } else {
-      clientHeader.push(`gl-web/${gaxModule.version}`);
+      clientHeader.push(`gl-web/${this._gaxModule.version}`);
     }
     if (!opts.fallback) {
-      clientHeader.push(`grpc/${gaxGrpc.grpcVersion}`);
+      clientHeader.push(`grpc/${this._gaxGrpc.grpcVersion}`);
     }
     if (opts.libName && opts.libVersion) {
       clientHeader.push(`${opts.libName}/${opts.libVersion}`);
@@ -122,7 +128,7 @@ export class AutoscalingPolicyServiceClient {
     // For browsers, pass the JSON content.
 
     const nodejsProtoPath = path.join(__dirname, '..', '..', 'protos', 'protos.json');
-    const protos = gaxGrpc.loadProto(
+    this._protos = this._gaxGrpc.loadProto(
       opts.fallback ?
         require("../../protos/protos.json") :
         nodejsProtoPath
@@ -132,16 +138,16 @@ export class AutoscalingPolicyServiceClient {
     // identifiers to uniquely identify resources within the API.
     // Create useful helper objects for these.
     this._pathTemplates = {
-      projectLocationAutoscalingPolicyPathTemplate: new gaxModule.PathTemplate(
+      projectLocationAutoscalingPolicyPathTemplate: new this._gaxModule.PathTemplate(
         'projects/{project}/locations/{location}/autoscalingPolicies/{autoscaling_policy}'
       ),
-      projectLocationWorkflowTemplatePathTemplate: new gaxModule.PathTemplate(
+      projectLocationWorkflowTemplatePathTemplate: new this._gaxModule.PathTemplate(
         'projects/{project}/locations/{location}/workflowTemplates/{workflow_template}'
       ),
-      projectRegionAutoscalingPolicyPathTemplate: new gaxModule.PathTemplate(
+      projectRegionAutoscalingPolicyPathTemplate: new this._gaxModule.PathTemplate(
         'projects/{project}/regions/{region}/autoscalingPolicies/{autoscaling_policy}'
       ),
-      projectRegionWorkflowTemplatePathTemplate: new gaxModule.PathTemplate(
+      projectRegionWorkflowTemplatePathTemplate: new this._gaxModule.PathTemplate(
         'projects/{project}/regions/{region}/workflowTemplates/{workflow_template}'
       ),
     };
@@ -151,11 +157,11 @@ export class AutoscalingPolicyServiceClient {
     // pages). Denote the keys used for pagination and results.
     this._descriptors.page = {
       listAutoscalingPolicies:
-          new gaxModule.PageDescriptor('pageToken', 'nextPageToken', 'policies')
+          new this._gaxModule.PageDescriptor('pageToken', 'nextPageToken', 'policies')
     };
 
     // Put together the default options sent with requests.
-    const defaults = gaxGrpc.constructSettings(
+    this._defaults = this._gaxGrpc.constructSettings(
         'google.cloud.dataproc.v1beta2.AutoscalingPolicyService', gapicConfig as gax.ClientConfig,
         opts.clientConfig || {}, {'x-goog-api-client': clientHeader.join(' ')});
 
@@ -163,15 +169,33 @@ export class AutoscalingPolicyServiceClient {
     // of calling the API is handled in `google-gax`, with this code
     // merely providing the destination and request information.
     this._innerApiCalls = {};
+  }
+
+  /**
+   * Initialize the client.
+   * Performs asynchronous operations (such as authentication) and prepares the client.
+   * This function will be called automatically when any class method is called for the
+   * first time, but if you need to initialize it before calling an actual method,
+   * feel free to call initialize() directly.
+   *
+   * You can await on this method if you want to make sure the client is initialized.
+   *
+   * @returns {Promise} A promise that resolves to an authenticated service stub.
+   */
+  initialize() {
+    // If the client stub promise is already initialized, return immediately.
+    if (this.autoscalingPolicyServiceStub) {
+      return this.autoscalingPolicyServiceStub;
+    }
 
     // Put together the "service stub" for
     // google.cloud.dataproc.v1beta2.AutoscalingPolicyService.
-    this.autoscalingPolicyServiceStub = gaxGrpc.createStub(
-        opts.fallback ?
-          (protos as protobuf.Root).lookupService('google.cloud.dataproc.v1beta2.AutoscalingPolicyService') :
+    this.autoscalingPolicyServiceStub = this._gaxGrpc.createStub(
+        this._opts.fallback ?
+          (this._protos as protobuf.Root).lookupService('google.cloud.dataproc.v1beta2.AutoscalingPolicyService') :
           // tslint:disable-next-line no-any
-          (protos as any).google.cloud.dataproc.v1beta2.AutoscalingPolicyService,
-        opts) as Promise<{[method: string]: Function}>;
+          (this._protos as any).google.cloud.dataproc.v1beta2.AutoscalingPolicyService,
+        this._opts) as Promise<{[method: string]: Function}>;
 
     // Iterate over each of the methods that the service provides
     // and create an API call method for each.
@@ -190,9 +214,9 @@ export class AutoscalingPolicyServiceClient {
           throw err;
         });
 
-      const apiCall = gaxModule.createApiCall(
+      const apiCall = this._gaxModule.createApiCall(
         innerCallPromise,
-        defaults[methodName],
+        this._defaults[methodName],
         this._descriptors.page[methodName] ||
             this._descriptors.stream[methodName] ||
             this._descriptors.longrunning[methodName]
@@ -206,6 +230,8 @@ export class AutoscalingPolicyServiceClient {
         return apiCall(argument, callOptions, callback);
       };
     }
+
+    return this.autoscalingPolicyServiceStub;
   }
 
   /**
@@ -327,6 +353,7 @@ export class AutoscalingPolicyServiceClient {
     ] = gax.routingHeader.fromParams({
       'parent': request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.createAutoscalingPolicy(request, options, callback);
   }
   updateAutoscalingPolicy(
@@ -389,6 +416,7 @@ export class AutoscalingPolicyServiceClient {
     ] = gax.routingHeader.fromParams({
       'policy.name': request.policy!.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.updateAutoscalingPolicy(request, options, callback);
   }
   getAutoscalingPolicy(
@@ -457,6 +485,7 @@ export class AutoscalingPolicyServiceClient {
     ] = gax.routingHeader.fromParams({
       'name': request.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.getAutoscalingPolicy(request, options, callback);
   }
   deleteAutoscalingPolicy(
@@ -526,6 +555,7 @@ export class AutoscalingPolicyServiceClient {
     ] = gax.routingHeader.fromParams({
       'name': request.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.deleteAutoscalingPolicy(request, options, callback);
   }
 
@@ -616,6 +646,7 @@ export class AutoscalingPolicyServiceClient {
     ] = gax.routingHeader.fromParams({
       'parent': request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.listAutoscalingPolicies(request, options, callback);
   }
 
@@ -670,6 +701,7 @@ export class AutoscalingPolicyServiceClient {
       'parent': request.parent || '',
     });
     const callSettings = new gax.CallSettings(options);
+    this.initialize();
     return this._descriptors.page.listAutoscalingPolicies.createStream(
       this._innerApiCalls.listAutoscalingPolicies as gax.GaxCall,
       request,
@@ -882,8 +914,9 @@ export class AutoscalingPolicyServiceClient {
    * The client will no longer be usable and all future behavior is undefined.
    */
   close(): Promise<void> {
+    this.initialize();
     if (!this._terminated) {
-      return this.autoscalingPolicyServiceStub.then(stub => {
+      return this.autoscalingPolicyServiceStub!.then(stub => {
         this._terminated = true;
         stub.close();
       });
diff --git a/packages/google-cloud-dataproc/src/v1beta2/cluster_controller_client.ts b/packages/google-cloud-dataproc/src/v1beta2/cluster_controller_client.ts
index dad2b4d10c9..6c10028267b 100644
--- a/packages/google-cloud-dataproc/src/v1beta2/cluster_controller_client.ts
+++ b/packages/google-cloud-dataproc/src/v1beta2/cluster_controller_client.ts
@@ -37,9 +37,14 @@ export class ClusterControllerClient {
   private _innerApiCalls: {[name: string]: Function};
   private _pathTemplates: {[name: string]: gax.PathTemplate};
   private _terminated = false;
+  private _opts: ClientOptions;
+  private _gaxModule: typeof gax | typeof gax.fallback;
+  private _gaxGrpc: gax.GrpcClient | gax.fallback.GrpcClient;
+  private _protos: {};
+  private _defaults: {[method: string]: gax.CallSettings};
   auth: gax.GoogleAuth;
   operationsClient: gax.OperationsClient;
-  clusterControllerStub: Promise<{[name: string]: Function}>;
+  clusterControllerStub?: Promise<{[name: string]: Function}>;
 
   /**
    * Construct an instance of ClusterControllerClient.
@@ -63,8 +68,6 @@ export class ClusterControllerClient {
    *     app is running in an environment which supports
    *     {@link https://developers.google.com/identity/protocols/application-default-credentials Application Default Credentials},
    *     your project ID will be detected automatically.
-   * @param {function} [options.promise] - Custom promise module to use instead
-   *     of native Promises.
    * @param {string} [options.apiEndpoint] - The domain name of the
    *     API remote host.
    */
@@ -92,28 +95,31 @@ export class ClusterControllerClient {
     // If we are in browser, we are already using fallback because of the
     // "browser" field in package.json.
     // But if we were explicitly requested to use fallback, let's do it now.
-    const gaxModule = !isBrowser && opts.fallback ? gax.fallback : gax;
+    this._gaxModule = !isBrowser && opts.fallback ? gax.fallback : gax;
 
     // Create a `gaxGrpc` object, with any grpc-specific options
     // sent to the client.
     opts.scopes = (this.constructor as typeof ClusterControllerClient).scopes;
-    const gaxGrpc = new gaxModule.GrpcClient(opts);
+    this._gaxGrpc = new this._gaxModule.GrpcClient(opts);
+
+    // Save options to use in initialize() method.
+    this._opts = opts;
 
     // Save the auth object to the client, for use by other methods.
-    this.auth = (gaxGrpc.auth as gax.GoogleAuth);
+    this.auth = (this._gaxGrpc.auth as gax.GoogleAuth);
 
     // Determine the client header string.
     const clientHeader = [
-      `gax/${gaxModule.version}`,
+      `gax/${this._gaxModule.version}`,
       `gapic/${version}`,
     ];
     if (typeof process !== 'undefined' && 'versions' in process) {
       clientHeader.push(`gl-node/${process.versions.node}`);
     } else {
-      clientHeader.push(`gl-web/${gaxModule.version}`);
+      clientHeader.push(`gl-web/${this._gaxModule.version}`);
     }
     if (!opts.fallback) {
-      clientHeader.push(`grpc/${gaxGrpc.grpcVersion}`);
+      clientHeader.push(`grpc/${this._gaxGrpc.grpcVersion}`);
     }
     if (opts.libName && opts.libVersion) {
       clientHeader.push(`${opts.libName}/${opts.libVersion}`);
@@ -123,7 +129,7 @@ export class ClusterControllerClient {
     // For browsers, pass the JSON content.
 
     const nodejsProtoPath = path.join(__dirname, '..', '..', 'protos', 'protos.json');
-    const protos = gaxGrpc.loadProto(
+    this._protos = this._gaxGrpc.loadProto(
       opts.fallback ?
         require("../../protos/protos.json") :
         nodejsProtoPath
@@ -133,16 +139,16 @@ export class ClusterControllerClient {
     // identifiers to uniquely identify resources within the API.
     // Create useful helper objects for these.
     this._pathTemplates = {
-      projectLocationAutoscalingPolicyPathTemplate: new gaxModule.PathTemplate(
+      projectLocationAutoscalingPolicyPathTemplate: new this._gaxModule.PathTemplate(
         'projects/{project}/locations/{location}/autoscalingPolicies/{autoscaling_policy}'
       ),
-      projectLocationWorkflowTemplatePathTemplate: new gaxModule.PathTemplate(
+      projectLocationWorkflowTemplatePathTemplate: new this._gaxModule.PathTemplate(
         'projects/{project}/locations/{location}/workflowTemplates/{workflow_template}'
       ),
-      projectRegionAutoscalingPolicyPathTemplate: new gaxModule.PathTemplate(
+      projectRegionAutoscalingPolicyPathTemplate: new this._gaxModule.PathTemplate(
         'projects/{project}/regions/{region}/autoscalingPolicies/{autoscaling_policy}'
       ),
-      projectRegionWorkflowTemplatePathTemplate: new gaxModule.PathTemplate(
+      projectRegionWorkflowTemplatePathTemplate: new this._gaxModule.PathTemplate(
         'projects/{project}/regions/{region}/workflowTemplates/{workflow_template}'
       ),
     };
@@ -152,19 +158,19 @@ export class ClusterControllerClient {
     // pages). Denote the keys used for pagination and results.
     this._descriptors.page = {
       listClusters:
-          new gaxModule.PageDescriptor('pageToken', 'nextPageToken', 'clusters')
+          new this._gaxModule.PageDescriptor('pageToken', 'nextPageToken', 'clusters')
     };
 
     // This API contains "long-running operations", which return a
     // an Operation object that allows for tracking of the operation,
     // rather than holding a request open.
     const protoFilesRoot = opts.fallback?
-      gaxModule.protobuf.Root.fromJSON(require("../../protos/protos.json")) :
-      gaxModule.protobuf.loadSync(nodejsProtoPath);
+      this._gaxModule.protobuf.Root.fromJSON(require("../../protos/protos.json")) :
+      this._gaxModule.protobuf.loadSync(nodejsProtoPath);
 
-    this.operationsClient = gaxModule.lro({
+    this.operationsClient = this._gaxModule.lro({
       auth: this.auth,
-      grpc: 'grpc' in gaxGrpc ? gaxGrpc.grpc : undefined
+      grpc: 'grpc' in this._gaxGrpc ? this._gaxGrpc.grpc : undefined
     }).operationsClient(opts);
     const createClusterResponse = protoFilesRoot.lookup(
       '.google.cloud.dataproc.v1beta2.Cluster') as gax.protobuf.Type;
@@ -184,26 +190,26 @@ export class ClusterControllerClient {
       '.google.cloud.dataproc.v1beta2.ClusterOperationMetadata') as gax.protobuf.Type;
 
     this._descriptors.longrunning = {
-      createCluster: new gaxModule.LongrunningDescriptor(
+      createCluster: new this._gaxModule.LongrunningDescriptor(
         this.operationsClient,
         createClusterResponse.decode.bind(createClusterResponse),
         createClusterMetadata.decode.bind(createClusterMetadata)),
-      updateCluster: new gaxModule.LongrunningDescriptor(
+      updateCluster: new this._gaxModule.LongrunningDescriptor(
         this.operationsClient,
         updateClusterResponse.decode.bind(updateClusterResponse),
         updateClusterMetadata.decode.bind(updateClusterMetadata)),
-      deleteCluster: new gaxModule.LongrunningDescriptor(
+      deleteCluster: new this._gaxModule.LongrunningDescriptor(
         this.operationsClient,
         deleteClusterResponse.decode.bind(deleteClusterResponse),
         deleteClusterMetadata.decode.bind(deleteClusterMetadata)),
-      diagnoseCluster: new gaxModule.LongrunningDescriptor(
+      diagnoseCluster: new this._gaxModule.LongrunningDescriptor(
         this.operationsClient,
         diagnoseClusterResponse.decode.bind(diagnoseClusterResponse),
         diagnoseClusterMetadata.decode.bind(diagnoseClusterMetadata))
     };
 
     // Put together the default options sent with requests.
-    const defaults = gaxGrpc.constructSettings(
+    this._defaults = this._gaxGrpc.constructSettings(
         'google.cloud.dataproc.v1beta2.ClusterController', gapicConfig as gax.ClientConfig,
         opts.clientConfig || {}, {'x-goog-api-client': clientHeader.join(' ')});
 
@@ -211,15 +217,33 @@ export class ClusterControllerClient {
     // of calling the API is handled in `google-gax`, with this code
     // merely providing the destination and request information.
     this._innerApiCalls = {};
+  }
+
+  /**
+   * Initialize the client.
+   * Performs asynchronous operations (such as authentication) and prepares the client.
+   * This function will be called automatically when any class method is called for the
+   * first time, but if you need to initialize it before calling an actual method,
+   * feel free to call initialize() directly.
+   *
+   * You can await on this method if you want to make sure the client is initialized.
+   *
+   * @returns {Promise} A promise that resolves to an authenticated service stub.
+   */
+  initialize() {
+    // If the client stub promise is already initialized, return immediately.
+    if (this.clusterControllerStub) {
+      return this.clusterControllerStub;
+    }
 
     // Put together the "service stub" for
     // google.cloud.dataproc.v1beta2.ClusterController.
-    this.clusterControllerStub = gaxGrpc.createStub(
-        opts.fallback ?
-          (protos as protobuf.Root).lookupService('google.cloud.dataproc.v1beta2.ClusterController') :
+    this.clusterControllerStub = this._gaxGrpc.createStub(
+        this._opts.fallback ?
+          (this._protos as protobuf.Root).lookupService('google.cloud.dataproc.v1beta2.ClusterController') :
           // tslint:disable-next-line no-any
-          (protos as any).google.cloud.dataproc.v1beta2.ClusterController,
-        opts) as Promise<{[method: string]: Function}>;
+          (this._protos as any).google.cloud.dataproc.v1beta2.ClusterController,
+        this._opts) as Promise<{[method: string]: Function}>;
 
     // Iterate over each of the methods that the service provides
     // and create an API call method for each.
@@ -238,9 +262,9 @@ export class ClusterControllerClient {
           throw err;
         });
 
-      const apiCall = gaxModule.createApiCall(
+      const apiCall = this._gaxModule.createApiCall(
         innerCallPromise,
-        defaults[methodName],
+        this._defaults[methodName],
         this._descriptors.page[methodName] ||
             this._descriptors.stream[methodName] ||
             this._descriptors.longrunning[methodName]
@@ -254,6 +278,8 @@ export class ClusterControllerClient {
         return apiCall(argument, callOptions, callback);
       };
     }
+
+    return this.clusterControllerStub;
   }
 
   /**
@@ -362,6 +388,7 @@ export class ClusterControllerClient {
       options = optionsOrCallback as gax.CallOptions;
     }
     options = options || {};
+    this.initialize();
     return this._innerApiCalls.getCluster(request, options, callback);
   }
 
@@ -381,7 +408,7 @@ export class ClusterControllerClient {
           {}|undefined>): void;
 /**
  * Creates a cluster in a project. The returned
- * [Operation.metadata][google.longrunning.Operation.metadata] will be
+ * {@link google.longrunning.Operation.metadata|Operation.metadata} will be
  * [ClusterOperationMetadata](https://cloud.google.com/dataproc/docs/reference/rpc/google.cloud.dataproc.v1beta2#clusteroperationmetadata).
  *
  * @param {Object} request
@@ -395,9 +422,9 @@ export class ClusterControllerClient {
  *   Required. The cluster to create.
  * @param {string} [request.requestId]
  *   Optional. A unique id used to identify the request. If the server
- *   receives two [CreateClusterRequest][google.cloud.dataproc.v1beta2.CreateClusterRequest] requests  with the same
+ *   receives two {@link google.cloud.dataproc.v1beta2.CreateClusterRequest|CreateClusterRequest} requests  with the same
  *   id, then the second request will be ignored and the
- *   first [google.longrunning.Operation][google.longrunning.Operation] created and stored in the backend
+ *   first {@link google.longrunning.Operation|google.longrunning.Operation} created and stored in the backend
  *   is returned.
  *
  *   It is recommended to always set this value to a
@@ -434,6 +461,7 @@ export class ClusterControllerClient {
       options = optionsOrCallback as gax.CallOptions;
     }
     options = options || {};
+    this.initialize();
     return this._innerApiCalls.createCluster(request, options, callback);
   }
   updateCluster(
@@ -452,7 +480,7 @@ export class ClusterControllerClient {
           {}|undefined>): void;
 /**
  * Updates a cluster in a project. The returned
- * [Operation.metadata][google.longrunning.Operation.metadata] will be
+ * {@link google.longrunning.Operation.metadata|Operation.metadata} will be
  * [ClusterOperationMetadata](https://cloud.google.com/dataproc/docs/reference/rpc/google.cloud.dataproc.v1beta2#clusteroperationmetadata).
  *
  * @param {Object} request
@@ -539,9 +567,9 @@ export class ClusterControllerClient {
  *   </table>
  * @param {string} [request.requestId]
  *   Optional. A unique id used to identify the request. If the server
- *   receives two [UpdateClusterRequest][google.cloud.dataproc.v1beta2.UpdateClusterRequest] requests  with the same
+ *   receives two {@link google.cloud.dataproc.v1beta2.UpdateClusterRequest|UpdateClusterRequest} requests  with the same
  *   id, then the second request will be ignored and the
- *   first [google.longrunning.Operation][google.longrunning.Operation] created and stored in the
+ *   first {@link google.longrunning.Operation|google.longrunning.Operation} created and stored in the
  *   backend is returned.
  *
  *   It is recommended to always set this value to a
@@ -578,6 +606,7 @@ export class ClusterControllerClient {
       options = optionsOrCallback as gax.CallOptions;
     }
     options = options || {};
+    this.initialize();
     return this._innerApiCalls.updateCluster(request, options, callback);
   }
   deleteCluster(
@@ -596,7 +625,7 @@ export class ClusterControllerClient {
           {}|undefined>): void;
 /**
  * Deletes a cluster in a project. The returned
- * [Operation.metadata][google.longrunning.Operation.metadata] will be
+ * {@link google.longrunning.Operation.metadata|Operation.metadata} will be
  * [ClusterOperationMetadata](https://cloud.google.com/dataproc/docs/reference/rpc/google.cloud.dataproc.v1beta2#clusteroperationmetadata).
  *
  * @param {Object} request
@@ -613,9 +642,9 @@ export class ClusterControllerClient {
  *   (with error NOT_FOUND) if cluster with specified UUID does not exist.
  * @param {string} [request.requestId]
  *   Optional. A unique id used to identify the request. If the server
- *   receives two [DeleteClusterRequest][google.cloud.dataproc.v1beta2.DeleteClusterRequest] requests  with the same
+ *   receives two {@link google.cloud.dataproc.v1beta2.DeleteClusterRequest|DeleteClusterRequest} requests  with the same
  *   id, then the second request will be ignored and the
- *   first [google.longrunning.Operation][google.longrunning.Operation] created and stored in the
+ *   first {@link google.longrunning.Operation|google.longrunning.Operation} created and stored in the
  *   backend is returned.
  *
  *   It is recommended to always set this value to a
@@ -652,6 +681,7 @@ export class ClusterControllerClient {
       options = optionsOrCallback as gax.CallOptions;
     }
     options = options || {};
+    this.initialize();
     return this._innerApiCalls.deleteCluster(request, options, callback);
   }
   diagnoseCluster(
@@ -670,12 +700,12 @@ export class ClusterControllerClient {
           {}|undefined>): void;
 /**
  * Gets cluster diagnostic information. The returned
- * [Operation.metadata][google.longrunning.Operation.metadata] will be
+ * {@link google.longrunning.Operation.metadata|Operation.metadata} will be
  * [ClusterOperationMetadata](https://cloud.google.com/dataproc/docs/reference/rpc/google.cloud.dataproc.v1beta2#clusteroperationmetadata).
  * After the operation completes,
- * [Operation.response][google.longrunning.Operation.response]
+ * {@link google.longrunning.Operation.response|Operation.response}
  * contains
- * [Empty][google.protobuf.Empty].
+ * {@link google.protobuf.Empty|Empty}.
  *
  * @param {Object} request
  *   The request object that will be sent.
@@ -715,6 +745,7 @@ export class ClusterControllerClient {
       options = optionsOrCallback as gax.CallOptions;
     }
     options = options || {};
+    this.initialize();
     return this._innerApiCalls.diagnoseCluster(request, options, callback);
   }
   listClusters(
@@ -809,6 +840,7 @@ export class ClusterControllerClient {
       options = optionsOrCallback as gax.CallOptions;
     }
     options = options || {};
+    this.initialize();
     return this._innerApiCalls.listClusters(request, options, callback);
   }
 
@@ -868,6 +900,7 @@ export class ClusterControllerClient {
     request = request || {};
     options = options || {};
     const callSettings = new gax.CallSettings(options);
+    this.initialize();
     return this._descriptors.page.listClusters.createStream(
       this._innerApiCalls.listClusters as gax.GaxCall,
       request,
@@ -1080,8 +1113,9 @@ export class ClusterControllerClient {
    * The client will no longer be usable and all future behavior is undefined.
    */
   close(): Promise<void> {
+    this.initialize();
     if (!this._terminated) {
-      return this.clusterControllerStub.then(stub => {
+      return this.clusterControllerStub!.then(stub => {
         this._terminated = true;
         stub.close();
       });
diff --git a/packages/google-cloud-dataproc/src/v1beta2/job_controller_client.ts b/packages/google-cloud-dataproc/src/v1beta2/job_controller_client.ts
index 141a294e6d9..07899705766 100644
--- a/packages/google-cloud-dataproc/src/v1beta2/job_controller_client.ts
+++ b/packages/google-cloud-dataproc/src/v1beta2/job_controller_client.ts
@@ -36,8 +36,13 @@ export class JobControllerClient {
   private _innerApiCalls: {[name: string]: Function};
   private _pathTemplates: {[name: string]: gax.PathTemplate};
   private _terminated = false;
+  private _opts: ClientOptions;
+  private _gaxModule: typeof gax | typeof gax.fallback;
+  private _gaxGrpc: gax.GrpcClient | gax.fallback.GrpcClient;
+  private _protos: {};
+  private _defaults: {[method: string]: gax.CallSettings};
   auth: gax.GoogleAuth;
-  jobControllerStub: Promise<{[name: string]: Function}>;
+  jobControllerStub?: Promise<{[name: string]: Function}>;
 
   /**
    * Construct an instance of JobControllerClient.
@@ -61,8 +66,6 @@ export class JobControllerClient {
    *     app is running in an environment which supports
    *     {@link https://developers.google.com/identity/protocols/application-default-credentials Application Default Credentials},
    *     your project ID will be detected automatically.
-   * @param {function} [options.promise] - Custom promise module to use instead
-   *     of native Promises.
    * @param {string} [options.apiEndpoint] - The domain name of the
    *     API remote host.
    */
@@ -90,28 +93,31 @@ export class JobControllerClient {
     // If we are in browser, we are already using fallback because of the
     // "browser" field in package.json.
     // But if we were explicitly requested to use fallback, let's do it now.
-    const gaxModule = !isBrowser && opts.fallback ? gax.fallback : gax;
+    this._gaxModule = !isBrowser && opts.fallback ? gax.fallback : gax;
 
     // Create a `gaxGrpc` object, with any grpc-specific options
     // sent to the client.
     opts.scopes = (this.constructor as typeof JobControllerClient).scopes;
-    const gaxGrpc = new gaxModule.GrpcClient(opts);
+    this._gaxGrpc = new this._gaxModule.GrpcClient(opts);
+
+    // Save options to use in initialize() method.
+    this._opts = opts;
 
     // Save the auth object to the client, for use by other methods.
-    this.auth = (gaxGrpc.auth as gax.GoogleAuth);
+    this.auth = (this._gaxGrpc.auth as gax.GoogleAuth);
 
     // Determine the client header string.
     const clientHeader = [
-      `gax/${gaxModule.version}`,
+      `gax/${this._gaxModule.version}`,
       `gapic/${version}`,
     ];
     if (typeof process !== 'undefined' && 'versions' in process) {
       clientHeader.push(`gl-node/${process.versions.node}`);
     } else {
-      clientHeader.push(`gl-web/${gaxModule.version}`);
+      clientHeader.push(`gl-web/${this._gaxModule.version}`);
     }
     if (!opts.fallback) {
-      clientHeader.push(`grpc/${gaxGrpc.grpcVersion}`);
+      clientHeader.push(`grpc/${this._gaxGrpc.grpcVersion}`);
     }
     if (opts.libName && opts.libVersion) {
       clientHeader.push(`${opts.libName}/${opts.libVersion}`);
@@ -121,7 +127,7 @@ export class JobControllerClient {
     // For browsers, pass the JSON content.
 
     const nodejsProtoPath = path.join(__dirname, '..', '..', 'protos', 'protos.json');
-    const protos = gaxGrpc.loadProto(
+    this._protos = this._gaxGrpc.loadProto(
       opts.fallback ?
         require("../../protos/protos.json") :
         nodejsProtoPath
@@ -131,16 +137,16 @@ export class JobControllerClient {
     // identifiers to uniquely identify resources within the API.
     // Create useful helper objects for these.
     this._pathTemplates = {
-      projectLocationAutoscalingPolicyPathTemplate: new gaxModule.PathTemplate(
+      projectLocationAutoscalingPolicyPathTemplate: new this._gaxModule.PathTemplate(
         'projects/{project}/locations/{location}/autoscalingPolicies/{autoscaling_policy}'
       ),
-      projectLocationWorkflowTemplatePathTemplate: new gaxModule.PathTemplate(
+      projectLocationWorkflowTemplatePathTemplate: new this._gaxModule.PathTemplate(
         'projects/{project}/locations/{location}/workflowTemplates/{workflow_template}'
       ),
-      projectRegionAutoscalingPolicyPathTemplate: new gaxModule.PathTemplate(
+      projectRegionAutoscalingPolicyPathTemplate: new this._gaxModule.PathTemplate(
         'projects/{project}/regions/{region}/autoscalingPolicies/{autoscaling_policy}'
       ),
-      projectRegionWorkflowTemplatePathTemplate: new gaxModule.PathTemplate(
+      projectRegionWorkflowTemplatePathTemplate: new this._gaxModule.PathTemplate(
         'projects/{project}/regions/{region}/workflowTemplates/{workflow_template}'
       ),
     };
@@ -150,11 +156,11 @@ export class JobControllerClient {
     // pages). Denote the keys used for pagination and results.
     this._descriptors.page = {
       listJobs:
-          new gaxModule.PageDescriptor('pageToken', 'nextPageToken', 'jobs')
+          new this._gaxModule.PageDescriptor('pageToken', 'nextPageToken', 'jobs')
     };
 
     // Put together the default options sent with requests.
-    const defaults = gaxGrpc.constructSettings(
+    this._defaults = this._gaxGrpc.constructSettings(
         'google.cloud.dataproc.v1beta2.JobController', gapicConfig as gax.ClientConfig,
         opts.clientConfig || {}, {'x-goog-api-client': clientHeader.join(' ')});
 
@@ -162,15 +168,33 @@ export class JobControllerClient {
     // of calling the API is handled in `google-gax`, with this code
     // merely providing the destination and request information.
     this._innerApiCalls = {};
+  }
+
+  /**
+   * Initialize the client.
+   * Performs asynchronous operations (such as authentication) and prepares the client.
+   * This function will be called automatically when any class method is called for the
+   * first time, but if you need to initialize it before calling an actual method,
+   * feel free to call initialize() directly.
+   *
+   * You can await on this method if you want to make sure the client is initialized.
+   *
+   * @returns {Promise} A promise that resolves to an authenticated service stub.
+   */
+  initialize() {
+    // If the client stub promise is already initialized, return immediately.
+    if (this.jobControllerStub) {
+      return this.jobControllerStub;
+    }
 
     // Put together the "service stub" for
     // google.cloud.dataproc.v1beta2.JobController.
-    this.jobControllerStub = gaxGrpc.createStub(
-        opts.fallback ?
-          (protos as protobuf.Root).lookupService('google.cloud.dataproc.v1beta2.JobController') :
+    this.jobControllerStub = this._gaxGrpc.createStub(
+        this._opts.fallback ?
+          (this._protos as protobuf.Root).lookupService('google.cloud.dataproc.v1beta2.JobController') :
           // tslint:disable-next-line no-any
-          (protos as any).google.cloud.dataproc.v1beta2.JobController,
-        opts) as Promise<{[method: string]: Function}>;
+          (this._protos as any).google.cloud.dataproc.v1beta2.JobController,
+        this._opts) as Promise<{[method: string]: Function}>;
 
     // Iterate over each of the methods that the service provides
     // and create an API call method for each.
@@ -189,9 +213,9 @@ export class JobControllerClient {
           throw err;
         });
 
-      const apiCall = gaxModule.createApiCall(
+      const apiCall = this._gaxModule.createApiCall(
         innerCallPromise,
-        defaults[methodName],
+        this._defaults[methodName],
         this._descriptors.page[methodName] ||
             this._descriptors.stream[methodName] ||
             this._descriptors.longrunning[methodName]
@@ -205,6 +229,8 @@ export class JobControllerClient {
         return apiCall(argument, callOptions, callback);
       };
     }
+
+    return this.jobControllerStub;
   }
 
   /**
@@ -286,9 +312,9 @@ export class JobControllerClient {
  *   Required. The job resource.
  * @param {string} [request.requestId]
  *   Optional. A unique id used to identify the request. If the server
- *   receives two [SubmitJobRequest][google.cloud.dataproc.v1beta2.SubmitJobRequest] requests  with the same
+ *   receives two {@link google.cloud.dataproc.v1beta2.SubmitJobRequest|SubmitJobRequest} requests  with the same
  *   id, then the second request will be ignored and the
- *   first [Job][google.cloud.dataproc.v1beta2.Job] created and stored in the backend
+ *   first {@link google.cloud.dataproc.v1beta2.Job|Job} created and stored in the backend
  *   is returned.
  *
  *   It is recommended to always set this value to a
@@ -325,6 +351,7 @@ export class JobControllerClient {
       options = optionsOrCallback as gax.CallOptions;
     }
     options = options || {};
+    this.initialize();
     return this._innerApiCalls.submitJob(request, options, callback);
   }
   getJob(
@@ -382,6 +409,7 @@ export class JobControllerClient {
       options = optionsOrCallback as gax.CallOptions;
     }
     options = options || {};
+    this.initialize();
     return this._innerApiCalls.getJob(request, options, callback);
   }
   updateJob(
@@ -448,6 +476,7 @@ export class JobControllerClient {
       options = optionsOrCallback as gax.CallOptions;
     }
     options = options || {};
+    this.initialize();
     return this._innerApiCalls.updateJob(request, options, callback);
   }
   cancelJob(
@@ -509,6 +538,7 @@ export class JobControllerClient {
       options = optionsOrCallback as gax.CallOptions;
     }
     options = options || {};
+    this.initialize();
     return this._innerApiCalls.cancelJob(request, options, callback);
   }
   deleteJob(
@@ -567,6 +597,7 @@ export class JobControllerClient {
       options = optionsOrCallback as gax.CallOptions;
     }
     options = options || {};
+    this.initialize();
     return this._innerApiCalls.deleteJob(request, options, callback);
   }
 
@@ -666,6 +697,7 @@ export class JobControllerClient {
       options = optionsOrCallback as gax.CallOptions;
     }
     options = options || {};
+    this.initialize();
     return this._innerApiCalls.listJobs(request, options, callback);
   }
 
@@ -729,6 +761,7 @@ export class JobControllerClient {
     request = request || {};
     options = options || {};
     const callSettings = new gax.CallSettings(options);
+    this.initialize();
     return this._descriptors.page.listJobs.createStream(
       this._innerApiCalls.listJobs as gax.GaxCall,
       request,
@@ -941,8 +974,9 @@ export class JobControllerClient {
    * The client will no longer be usable and all future behavior is undefined.
    */
   close(): Promise<void> {
+    this.initialize();
     if (!this._terminated) {
-      return this.jobControllerStub.then(stub => {
+      return this.jobControllerStub!.then(stub => {
         this._terminated = true;
         stub.close();
       });
diff --git a/packages/google-cloud-dataproc/src/v1beta2/workflow_template_service_client.ts b/packages/google-cloud-dataproc/src/v1beta2/workflow_template_service_client.ts
index 964bfe40df6..3dc647a6084 100644
--- a/packages/google-cloud-dataproc/src/v1beta2/workflow_template_service_client.ts
+++ b/packages/google-cloud-dataproc/src/v1beta2/workflow_template_service_client.ts
@@ -37,9 +37,14 @@ export class WorkflowTemplateServiceClient {
   private _innerApiCalls: {[name: string]: Function};
   private _pathTemplates: {[name: string]: gax.PathTemplate};
   private _terminated = false;
+  private _opts: ClientOptions;
+  private _gaxModule: typeof gax | typeof gax.fallback;
+  private _gaxGrpc: gax.GrpcClient | gax.fallback.GrpcClient;
+  private _protos: {};
+  private _defaults: {[method: string]: gax.CallSettings};
   auth: gax.GoogleAuth;
   operationsClient: gax.OperationsClient;
-  workflowTemplateServiceStub: Promise<{[name: string]: Function}>;
+  workflowTemplateServiceStub?: Promise<{[name: string]: Function}>;
 
   /**
    * Construct an instance of WorkflowTemplateServiceClient.
@@ -63,8 +68,6 @@ export class WorkflowTemplateServiceClient {
    *     app is running in an environment which supports
    *     {@link https://developers.google.com/identity/protocols/application-default-credentials Application Default Credentials},
    *     your project ID will be detected automatically.
-   * @param {function} [options.promise] - Custom promise module to use instead
-   *     of native Promises.
    * @param {string} [options.apiEndpoint] - The domain name of the
    *     API remote host.
    */
@@ -92,28 +95,31 @@ export class WorkflowTemplateServiceClient {
     // If we are in browser, we are already using fallback because of the
     // "browser" field in package.json.
     // But if we were explicitly requested to use fallback, let's do it now.
-    const gaxModule = !isBrowser && opts.fallback ? gax.fallback : gax;
+    this._gaxModule = !isBrowser && opts.fallback ? gax.fallback : gax;
 
     // Create a `gaxGrpc` object, with any grpc-specific options
     // sent to the client.
     opts.scopes = (this.constructor as typeof WorkflowTemplateServiceClient).scopes;
-    const gaxGrpc = new gaxModule.GrpcClient(opts);
+    this._gaxGrpc = new this._gaxModule.GrpcClient(opts);
+
+    // Save options to use in initialize() method.
+    this._opts = opts;
 
     // Save the auth object to the client, for use by other methods.
-    this.auth = (gaxGrpc.auth as gax.GoogleAuth);
+    this.auth = (this._gaxGrpc.auth as gax.GoogleAuth);
 
     // Determine the client header string.
     const clientHeader = [
-      `gax/${gaxModule.version}`,
+      `gax/${this._gaxModule.version}`,
       `gapic/${version}`,
     ];
     if (typeof process !== 'undefined' && 'versions' in process) {
       clientHeader.push(`gl-node/${process.versions.node}`);
     } else {
-      clientHeader.push(`gl-web/${gaxModule.version}`);
+      clientHeader.push(`gl-web/${this._gaxModule.version}`);
     }
     if (!opts.fallback) {
-      clientHeader.push(`grpc/${gaxGrpc.grpcVersion}`);
+      clientHeader.push(`grpc/${this._gaxGrpc.grpcVersion}`);
     }
     if (opts.libName && opts.libVersion) {
       clientHeader.push(`${opts.libName}/${opts.libVersion}`);
@@ -123,7 +129,7 @@ export class WorkflowTemplateServiceClient {
     // For browsers, pass the JSON content.
 
     const nodejsProtoPath = path.join(__dirname, '..', '..', 'protos', 'protos.json');
-    const protos = gaxGrpc.loadProto(
+    this._protos = this._gaxGrpc.loadProto(
       opts.fallback ?
         require("../../protos/protos.json") :
         nodejsProtoPath
@@ -133,16 +139,16 @@ export class WorkflowTemplateServiceClient {
     // identifiers to uniquely identify resources within the API.
     // Create useful helper objects for these.
     this._pathTemplates = {
-      projectLocationAutoscalingPolicyPathTemplate: new gaxModule.PathTemplate(
+      projectLocationAutoscalingPolicyPathTemplate: new this._gaxModule.PathTemplate(
         'projects/{project}/locations/{location}/autoscalingPolicies/{autoscaling_policy}'
       ),
-      projectLocationWorkflowTemplatePathTemplate: new gaxModule.PathTemplate(
+      projectLocationWorkflowTemplatePathTemplate: new this._gaxModule.PathTemplate(
         'projects/{project}/locations/{location}/workflowTemplates/{workflow_template}'
       ),
-      projectRegionAutoscalingPolicyPathTemplate: new gaxModule.PathTemplate(
+      projectRegionAutoscalingPolicyPathTemplate: new this._gaxModule.PathTemplate(
         'projects/{project}/regions/{region}/autoscalingPolicies/{autoscaling_policy}'
       ),
-      projectRegionWorkflowTemplatePathTemplate: new gaxModule.PathTemplate(
+      projectRegionWorkflowTemplatePathTemplate: new this._gaxModule.PathTemplate(
         'projects/{project}/regions/{region}/workflowTemplates/{workflow_template}'
       ),
     };
@@ -152,19 +158,19 @@ export class WorkflowTemplateServiceClient {
     // pages). Denote the keys used for pagination and results.
     this._descriptors.page = {
       listWorkflowTemplates:
-          new gaxModule.PageDescriptor('pageToken', 'nextPageToken', 'templates')
+          new this._gaxModule.PageDescriptor('pageToken', 'nextPageToken', 'templates')
     };
 
     // This API contains "long-running operations", which return a
     // an Operation object that allows for tracking of the operation,
     // rather than holding a request open.
     const protoFilesRoot = opts.fallback?
-      gaxModule.protobuf.Root.fromJSON(require("../../protos/protos.json")) :
-      gaxModule.protobuf.loadSync(nodejsProtoPath);
+      this._gaxModule.protobuf.Root.fromJSON(require("../../protos/protos.json")) :
+      this._gaxModule.protobuf.loadSync(nodejsProtoPath);
 
-    this.operationsClient = gaxModule.lro({
+    this.operationsClient = this._gaxModule.lro({
       auth: this.auth,
-      grpc: 'grpc' in gaxGrpc ? gaxGrpc.grpc : undefined
+      grpc: 'grpc' in this._gaxGrpc ? this._gaxGrpc.grpc : undefined
     }).operationsClient(opts);
     const instantiateWorkflowTemplateResponse = protoFilesRoot.lookup(
       '.google.protobuf.Empty') as gax.protobuf.Type;
@@ -176,18 +182,18 @@ export class WorkflowTemplateServiceClient {
       '.google.cloud.dataproc.v1beta2.WorkflowMetadata') as gax.protobuf.Type;
 
     this._descriptors.longrunning = {
-      instantiateWorkflowTemplate: new gaxModule.LongrunningDescriptor(
+      instantiateWorkflowTemplate: new this._gaxModule.LongrunningDescriptor(
         this.operationsClient,
         instantiateWorkflowTemplateResponse.decode.bind(instantiateWorkflowTemplateResponse),
         instantiateWorkflowTemplateMetadata.decode.bind(instantiateWorkflowTemplateMetadata)),
-      instantiateInlineWorkflowTemplate: new gaxModule.LongrunningDescriptor(
+      instantiateInlineWorkflowTemplate: new this._gaxModule.LongrunningDescriptor(
         this.operationsClient,
         instantiateInlineWorkflowTemplateResponse.decode.bind(instantiateInlineWorkflowTemplateResponse),
         instantiateInlineWorkflowTemplateMetadata.decode.bind(instantiateInlineWorkflowTemplateMetadata))
     };
 
     // Put together the default options sent with requests.
-    const defaults = gaxGrpc.constructSettings(
+    this._defaults = this._gaxGrpc.constructSettings(
         'google.cloud.dataproc.v1beta2.WorkflowTemplateService', gapicConfig as gax.ClientConfig,
         opts.clientConfig || {}, {'x-goog-api-client': clientHeader.join(' ')});
 
@@ -195,15 +201,33 @@ export class WorkflowTemplateServiceClient {
     // of calling the API is handled in `google-gax`, with this code
     // merely providing the destination and request information.
     this._innerApiCalls = {};
+  }
+
+  /**
+   * Initialize the client.
+   * Performs asynchronous operations (such as authentication) and prepares the client.
+   * This function will be called automatically when any class method is called for the
+   * first time, but if you need to initialize it before calling an actual method,
+   * feel free to call initialize() directly.
+   *
+   * You can await on this method if you want to make sure the client is initialized.
+   *
+   * @returns {Promise} A promise that resolves to an authenticated service stub.
+   */
+  initialize() {
+    // If the client stub promise is already initialized, return immediately.
+    if (this.workflowTemplateServiceStub) {
+      return this.workflowTemplateServiceStub;
+    }
 
     // Put together the "service stub" for
     // google.cloud.dataproc.v1beta2.WorkflowTemplateService.
-    this.workflowTemplateServiceStub = gaxGrpc.createStub(
-        opts.fallback ?
-          (protos as protobuf.Root).lookupService('google.cloud.dataproc.v1beta2.WorkflowTemplateService') :
+    this.workflowTemplateServiceStub = this._gaxGrpc.createStub(
+        this._opts.fallback ?
+          (this._protos as protobuf.Root).lookupService('google.cloud.dataproc.v1beta2.WorkflowTemplateService') :
           // tslint:disable-next-line no-any
-          (protos as any).google.cloud.dataproc.v1beta2.WorkflowTemplateService,
-        opts) as Promise<{[method: string]: Function}>;
+          (this._protos as any).google.cloud.dataproc.v1beta2.WorkflowTemplateService,
+        this._opts) as Promise<{[method: string]: Function}>;
 
     // Iterate over each of the methods that the service provides
     // and create an API call method for each.
@@ -222,9 +246,9 @@ export class WorkflowTemplateServiceClient {
           throw err;
         });
 
-      const apiCall = gaxModule.createApiCall(
+      const apiCall = this._gaxModule.createApiCall(
         innerCallPromise,
-        defaults[methodName],
+        this._defaults[methodName],
         this._descriptors.page[methodName] ||
             this._descriptors.stream[methodName] ||
             this._descriptors.longrunning[methodName]
@@ -238,6 +262,8 @@ export class WorkflowTemplateServiceClient {
         return apiCall(argument, callOptions, callback);
       };
     }
+
+    return this.workflowTemplateServiceStub;
   }
 
   /**
@@ -359,6 +385,7 @@ export class WorkflowTemplateServiceClient {
     ] = gax.routingHeader.fromParams({
       'parent': request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.createWorkflowTemplate(request, options, callback);
   }
   getWorkflowTemplate(
@@ -435,6 +462,7 @@ export class WorkflowTemplateServiceClient {
     ] = gax.routingHeader.fromParams({
       'name': request.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.getWorkflowTemplate(request, options, callback);
   }
   updateWorkflowTemplate(
@@ -497,6 +525,7 @@ export class WorkflowTemplateServiceClient {
     ] = gax.routingHeader.fromParams({
       'template.name': request.template!.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.updateWorkflowTemplate(request, options, callback);
   }
   deleteWorkflowTemplate(
@@ -569,6 +598,7 @@ export class WorkflowTemplateServiceClient {
     ] = gax.routingHeader.fromParams({
       'name': request.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.deleteWorkflowTemplate(request, options, callback);
   }
 
@@ -591,22 +621,22 @@ export class WorkflowTemplateServiceClient {
  *
  * The returned Operation can be used to track execution of
  * workflow by polling
- * [operations.get][google.longrunning.Operations.GetOperation].
+ * {@link google.longrunning.Operations.GetOperation|operations.get}.
  * The Operation will complete when entire workflow is finished.
  *
  * The running workflow can be aborted via
- * [operations.cancel][google.longrunning.Operations.CancelOperation].
+ * {@link google.longrunning.Operations.CancelOperation|operations.cancel}.
  * This will cause any inflight jobs to be cancelled and workflow-owned
  * clusters to be deleted.
  *
- * The [Operation.metadata][google.longrunning.Operation.metadata] will be
+ * The {@link google.longrunning.Operation.metadata|Operation.metadata} will be
  * [WorkflowMetadata](https://cloud.google.com/dataproc/docs/reference/rpc/google.cloud.dataproc.v1beta2#workflowmetadata).
  * Also see [Using
  * WorkflowMetadata](https://cloud.google.com/dataproc/docs/concepts/workflows/debugging#using_workflowmetadata).
  *
  * On successful completion,
- * [Operation.response][google.longrunning.Operation.response] will be
- * [Empty][google.protobuf.Empty].
+ * {@link google.longrunning.Operation.response|Operation.response} will be
+ * {@link google.protobuf.Empty|Empty}.
  *
  * @param {Object} request
  *   The request object that will be sent.
@@ -679,6 +709,7 @@ export class WorkflowTemplateServiceClient {
     ] = gax.routingHeader.fromParams({
       'name': request.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.instantiateWorkflowTemplate(request, options, callback);
   }
   instantiateInlineWorkflowTemplate(
@@ -699,27 +730,27 @@ export class WorkflowTemplateServiceClient {
  * Instantiates a template and begins execution.
  *
  * This method is equivalent to executing the sequence
- * [CreateWorkflowTemplate][google.cloud.dataproc.v1beta2.WorkflowTemplateService.CreateWorkflowTemplate], [InstantiateWorkflowTemplate][google.cloud.dataproc.v1beta2.WorkflowTemplateService.InstantiateWorkflowTemplate],
- * [DeleteWorkflowTemplate][google.cloud.dataproc.v1beta2.WorkflowTemplateService.DeleteWorkflowTemplate].
+ * {@link google.cloud.dataproc.v1beta2.WorkflowTemplateService.CreateWorkflowTemplate|CreateWorkflowTemplate}, {@link google.cloud.dataproc.v1beta2.WorkflowTemplateService.InstantiateWorkflowTemplate|InstantiateWorkflowTemplate},
+ * {@link google.cloud.dataproc.v1beta2.WorkflowTemplateService.DeleteWorkflowTemplate|DeleteWorkflowTemplate}.
  *
  * The returned Operation can be used to track execution of
  * workflow by polling
- * [operations.get][google.longrunning.Operations.GetOperation].
+ * {@link google.longrunning.Operations.GetOperation|operations.get}.
  * The Operation will complete when entire workflow is finished.
  *
  * The running workflow can be aborted via
- * [operations.cancel][google.longrunning.Operations.CancelOperation].
+ * {@link google.longrunning.Operations.CancelOperation|operations.cancel}.
  * This will cause any inflight jobs to be cancelled and workflow-owned
  * clusters to be deleted.
  *
- * The [Operation.metadata][google.longrunning.Operation.metadata] will be
+ * The {@link google.longrunning.Operation.metadata|Operation.metadata} will be
  * [WorkflowMetadata](https://cloud.google.com/dataproc/docs/reference/rpc/google.cloud.dataproc.v1#workflowmetadata).
  * Also see [Using
  * WorkflowMetadata](https://cloud.google.com/dataproc/docs/concepts/workflows/debugging#using_workflowmetadata).
  *
  * On successful completion,
- * [Operation.response][google.longrunning.Operation.response] will be
- * [Empty][google.protobuf.Empty].
+ * {@link google.longrunning.Operation.response|Operation.response} will be
+ * {@link google.protobuf.Empty|Empty}.
  *
  * @param {Object} request
  *   The request object that will be sent.
@@ -784,6 +815,7 @@ export class WorkflowTemplateServiceClient {
     ] = gax.routingHeader.fromParams({
       'parent': request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.instantiateInlineWorkflowTemplate(request, options, callback);
   }
   listWorkflowTemplates(
@@ -872,6 +904,7 @@ export class WorkflowTemplateServiceClient {
     ] = gax.routingHeader.fromParams({
       'parent': request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.listWorkflowTemplates(request, options, callback);
   }
 
@@ -925,6 +958,7 @@ export class WorkflowTemplateServiceClient {
       'parent': request.parent || '',
     });
     const callSettings = new gax.CallSettings(options);
+    this.initialize();
     return this._descriptors.page.listWorkflowTemplates.createStream(
       this._innerApiCalls.listWorkflowTemplates as gax.GaxCall,
       request,
@@ -1137,8 +1171,9 @@ export class WorkflowTemplateServiceClient {
    * The client will no longer be usable and all future behavior is undefined.
    */
   close(): Promise<void> {
+    this.initialize();
     if (!this._terminated) {
-      return this.workflowTemplateServiceStub.then(stub => {
+      return this.workflowTemplateServiceStub!.then(stub => {
         this._terminated = true;
         stub.close();
       });
diff --git a/packages/google-cloud-dataproc/synth.metadata b/packages/google-cloud-dataproc/synth.metadata
index 26d835425ce..441fe5d8e59 100644
--- a/packages/google-cloud-dataproc/synth.metadata
+++ b/packages/google-cloud-dataproc/synth.metadata
@@ -1,13 +1,13 @@
 {
-  "updateTime": "2020-03-01T12:21:45.590214Z",
+  "updateTime": "2020-03-05T23:05:26.554565Z",
   "sources": [
     {
       "git": {
         "name": "googleapis",
         "remote": "https://github.com/googleapis/googleapis.git",
-        "sha": "83c6f84035ee0f80eaa44d8b688a010461cc4080",
-        "internalRef": "297918498",
-        "log": "83c6f84035ee0f80eaa44d8b688a010461cc4080\nUpdate google/api/auth.proto to make AuthProvider to have JwtLocation\n\nPiperOrigin-RevId: 297918498\n\ne9e90a787703ec5d388902e2cb796aaed3a385b4\nDialogflow weekly v2/v2beta1 library update:\n  - adding get validation result\n  - adding field mask override control for output audio config\nImportant updates are also posted at:\nhttps://cloud.google.com/dialogflow/docs/release-notes\n\nPiperOrigin-RevId: 297671458\n\n1a2b05cc3541a5f7714529c665aecc3ea042c646\nAdding .yaml and .json config files.\n\nPiperOrigin-RevId: 297570622\n\ndfe1cf7be44dee31d78f78e485d8c95430981d6e\nPublish `QueryOptions` proto.\n\nIntroduced a `query_options` input in `ExecuteSqlRequest`.\n\nPiperOrigin-RevId: 297497710\n\ndafc905f71e5d46f500b41ed715aad585be062c3\npubsub: revert pull init_rpc_timeout & max_rpc_timeout back to 25 seconds and reset multiplier to 1.0\n\nPiperOrigin-RevId: 297486523\n\nf077632ba7fee588922d9e8717ee272039be126d\nfirestore: add update_transform\n\nPiperOrigin-RevId: 297405063\n\n"
+        "sha": "f0b581b5bdf803e45201ecdb3688b60e381628a8",
+        "internalRef": "299181282",
+        "log": "f0b581b5bdf803e45201ecdb3688b60e381628a8\nfix: recommendationengine/v1beta1 update some comments\n\nPiperOrigin-RevId: 299181282\n\n10e9a0a833dc85ff8f05b2c67ebe5ac785fe04ff\nbuild: add generated BUILD file for Routes Preferred API\n\nPiperOrigin-RevId: 299164808\n\n86738c956a8238d7c77f729be78b0ed887a6c913\npublish v1p1beta1: update with absolute address in comments\n\nPiperOrigin-RevId: 299152383\n\n73d9f2ad4591de45c2e1f352bc99d70cbd2a6d95\npublish v1: update with absolute address in comments\n\nPiperOrigin-RevId: 299147194\n\nd2158f24cb77b0b0ccfe68af784c6a628705e3c6\npublish v1beta2: update with absolute address in comments\n\nPiperOrigin-RevId: 299147086\n\n7fca61292c11b4cd5b352cee1a50bf88819dd63b\npublish v1p2beta1: update with absolute address in comments\n\nPiperOrigin-RevId: 299146903\n\n583b7321624736e2c490e328f4b1957335779295\npublish v1p3beta1: update with absolute address in comments\n\nPiperOrigin-RevId: 299146674\n\n638253bf86d1ce1c314108a089b7351440c2f0bf\nfix: add java_multiple_files option for automl text_sentiment.proto\n\nPiperOrigin-RevId: 298971070\n\n373d655703bf914fb8b0b1cc4071d772bac0e0d1\nUpdate Recs AI Beta public bazel file\n\nPiperOrigin-RevId: 298961623\n\ndcc5d00fc8a8d8b56f16194d7c682027b2c66a3b\nfix: add java_multiple_files option for automl classification.proto\n\nPiperOrigin-RevId: 298953301\n\na3f791827266f3496a6a5201d58adc4bb265c2a3\nchore: automl/v1 publish annotations and retry config\n\nPiperOrigin-RevId: 298942178\n\n01c681586d8d6dbd60155289b587aee678530bd9\nMark return_immediately in PullRequest deprecated.\n\nPiperOrigin-RevId: 298893281\n\nc9f5e9c4bfed54bbd09227e990e7bded5f90f31c\nRemove out of date documentation for predicate support on the Storage API\n\nPiperOrigin-RevId: 298883309\n\nfd5b3b8238d783b04692a113ffe07c0363f5de0f\ngenerate webrisk v1 proto\n\nPiperOrigin-RevId: 298847934\n\n541b1ded4abadcc38e8178680b0677f65594ea6f\nUpdate cloud asset api v1p4beta1.\n\nPiperOrigin-RevId: 298686266\n\nc0d171acecb4f5b0bfd2c4ca34fc54716574e300\n  Updated to include the Notification v1 API.\n\nPiperOrigin-RevId: 298652775\n\n2346a9186c0bff2c9cc439f2459d558068637e05\nAdd Service Directory v1beta1 protos and configs\n\nPiperOrigin-RevId: 298625638\n\na78ed801b82a5c6d9c5368e24b1412212e541bb7\nPublishing v3 protos and configs.\n\nPiperOrigin-RevId: 298607357\n\n4a180bfff8a21645b3a935c2756e8d6ab18a74e0\nautoml/v1beta1 publish proto updates\n\nPiperOrigin-RevId: 298484782\n\n6de6e938b7df1cd62396563a067334abeedb9676\nchore: use the latest gapic-generator and protoc-java-resource-name-plugin in Bazel workspace.\n\nPiperOrigin-RevId: 298474513\n\n244ab2b83a82076a1fa7be63b7e0671af73f5c02\nAdds service config definition for bigqueryreservation v1\n\nPiperOrigin-RevId: 298455048\n\n"
       }
     },
     {
diff --git a/packages/google-cloud-dataproc/test/gapic-autoscaling_policy_service-v1.ts b/packages/google-cloud-dataproc/test/gapic-autoscaling_policy_service-v1.ts
index e07adcdf9cf..890c8e0774a 100644
--- a/packages/google-cloud-dataproc/test/gapic-autoscaling_policy_service-v1.ts
+++ b/packages/google-cloud-dataproc/test/gapic-autoscaling_policy_service-v1.ts
@@ -78,12 +78,30 @@ describe('v1.AutoscalingPolicyServiceClient', () => {
         });
         assert(client);
     });
+    it('has initialize method and supports deferred initialization', async () => {
+        const client = new autoscalingpolicyserviceModule.v1.AutoscalingPolicyServiceClient({
+            credentials: { client_email: 'bogus', private_key: 'bogus' },
+            projectId: 'bogus',
+        });
+        assert.strictEqual(client.autoscalingPolicyServiceStub, undefined);
+        await client.initialize();
+        assert(client.autoscalingPolicyServiceStub);
+    });
+    it('has close method', () => {
+        const client = new autoscalingpolicyserviceModule.v1.AutoscalingPolicyServiceClient({
+            credentials: { client_email: 'bogus', private_key: 'bogus' },
+            projectId: 'bogus',
+        });
+        client.close();
+    });
     describe('createAutoscalingPolicy', () => {
         it('invokes createAutoscalingPolicy without error', done => {
             const client = new autoscalingpolicyserviceModule.v1.AutoscalingPolicyServiceClient({
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.ICreateAutoscalingPolicyRequest = {};
             request.parent = '';
@@ -107,6 +125,8 @@ describe('v1.AutoscalingPolicyServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.ICreateAutoscalingPolicyRequest = {};
             request.parent = '';
@@ -132,6 +152,8 @@ describe('v1.AutoscalingPolicyServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IUpdateAutoscalingPolicyRequest = {};
             request.policy = {};
@@ -156,6 +178,8 @@ describe('v1.AutoscalingPolicyServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IUpdateAutoscalingPolicyRequest = {};
             request.policy = {};
@@ -182,6 +206,8 @@ describe('v1.AutoscalingPolicyServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IGetAutoscalingPolicyRequest = {};
             request.name = '';
@@ -205,6 +231,8 @@ describe('v1.AutoscalingPolicyServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IGetAutoscalingPolicyRequest = {};
             request.name = '';
@@ -230,6 +258,8 @@ describe('v1.AutoscalingPolicyServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IDeleteAutoscalingPolicyRequest = {};
             request.name = '';
@@ -253,6 +283,8 @@ describe('v1.AutoscalingPolicyServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IDeleteAutoscalingPolicyRequest = {};
             request.name = '';
@@ -278,6 +310,8 @@ describe('v1.AutoscalingPolicyServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IListAutoscalingPoliciesRequest = {};
             request.parent = '';
@@ -301,6 +335,8 @@ describe('v1.AutoscalingPolicyServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IListAutoscalingPoliciesRequest = {};
             request.parent = '';
diff --git a/packages/google-cloud-dataproc/test/gapic-autoscaling_policy_service-v1beta2.ts b/packages/google-cloud-dataproc/test/gapic-autoscaling_policy_service-v1beta2.ts
index c983e633e93..463f428dda0 100644
--- a/packages/google-cloud-dataproc/test/gapic-autoscaling_policy_service-v1beta2.ts
+++ b/packages/google-cloud-dataproc/test/gapic-autoscaling_policy_service-v1beta2.ts
@@ -78,12 +78,30 @@ describe('v1beta2.AutoscalingPolicyServiceClient', () => {
         });
         assert(client);
     });
+    it('has initialize method and supports deferred initialization', async () => {
+        const client = new autoscalingpolicyserviceModule.v1beta2.AutoscalingPolicyServiceClient({
+            credentials: { client_email: 'bogus', private_key: 'bogus' },
+            projectId: 'bogus',
+        });
+        assert.strictEqual(client.autoscalingPolicyServiceStub, undefined);
+        await client.initialize();
+        assert(client.autoscalingPolicyServiceStub);
+    });
+    it('has close method', () => {
+        const client = new autoscalingpolicyserviceModule.v1beta2.AutoscalingPolicyServiceClient({
+            credentials: { client_email: 'bogus', private_key: 'bogus' },
+            projectId: 'bogus',
+        });
+        client.close();
+    });
     describe('createAutoscalingPolicy', () => {
         it('invokes createAutoscalingPolicy without error', done => {
             const client = new autoscalingpolicyserviceModule.v1beta2.AutoscalingPolicyServiceClient({
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.ICreateAutoscalingPolicyRequest = {};
             request.parent = '';
@@ -107,6 +125,8 @@ describe('v1beta2.AutoscalingPolicyServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.ICreateAutoscalingPolicyRequest = {};
             request.parent = '';
@@ -132,6 +152,8 @@ describe('v1beta2.AutoscalingPolicyServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IUpdateAutoscalingPolicyRequest = {};
             request.policy = {};
@@ -156,6 +178,8 @@ describe('v1beta2.AutoscalingPolicyServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IUpdateAutoscalingPolicyRequest = {};
             request.policy = {};
@@ -182,6 +206,8 @@ describe('v1beta2.AutoscalingPolicyServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IGetAutoscalingPolicyRequest = {};
             request.name = '';
@@ -205,6 +231,8 @@ describe('v1beta2.AutoscalingPolicyServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IGetAutoscalingPolicyRequest = {};
             request.name = '';
@@ -230,6 +258,8 @@ describe('v1beta2.AutoscalingPolicyServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IDeleteAutoscalingPolicyRequest = {};
             request.name = '';
@@ -253,6 +283,8 @@ describe('v1beta2.AutoscalingPolicyServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IDeleteAutoscalingPolicyRequest = {};
             request.name = '';
@@ -278,6 +310,8 @@ describe('v1beta2.AutoscalingPolicyServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IListAutoscalingPoliciesRequest = {};
             request.parent = '';
@@ -301,6 +335,8 @@ describe('v1beta2.AutoscalingPolicyServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IListAutoscalingPoliciesRequest = {};
             request.parent = '';
diff --git a/packages/google-cloud-dataproc/test/gapic-cluster_controller-v1.ts b/packages/google-cloud-dataproc/test/gapic-cluster_controller-v1.ts
index e6538802d87..7204f54c799 100644
--- a/packages/google-cloud-dataproc/test/gapic-cluster_controller-v1.ts
+++ b/packages/google-cloud-dataproc/test/gapic-cluster_controller-v1.ts
@@ -96,12 +96,30 @@ describe('v1.ClusterControllerClient', () => {
         });
         assert(client);
     });
+    it('has initialize method and supports deferred initialization', async () => {
+        const client = new clustercontrollerModule.v1.ClusterControllerClient({
+            credentials: { client_email: 'bogus', private_key: 'bogus' },
+            projectId: 'bogus',
+        });
+        assert.strictEqual(client.clusterControllerStub, undefined);
+        await client.initialize();
+        assert(client.clusterControllerStub);
+    });
+    it('has close method', () => {
+        const client = new clustercontrollerModule.v1.ClusterControllerClient({
+            credentials: { client_email: 'bogus', private_key: 'bogus' },
+            projectId: 'bogus',
+        });
+        client.close();
+    });
     describe('getCluster', () => {
         it('invokes getCluster without error', done => {
             const client = new clustercontrollerModule.v1.ClusterControllerClient({
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IGetClusterRequest = {};
             // Mock response
@@ -124,6 +142,8 @@ describe('v1.ClusterControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IGetClusterRequest = {};
             // Mock response
@@ -148,6 +168,8 @@ describe('v1.ClusterControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.ICreateClusterRequest = {};
             // Mock response
@@ -173,6 +195,8 @@ describe('v1.ClusterControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.ICreateClusterRequest = {};
             // Mock response
@@ -201,6 +225,8 @@ describe('v1.ClusterControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IUpdateClusterRequest = {};
             // Mock response
@@ -226,6 +252,8 @@ describe('v1.ClusterControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IUpdateClusterRequest = {};
             // Mock response
@@ -254,6 +282,8 @@ describe('v1.ClusterControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IDeleteClusterRequest = {};
             // Mock response
@@ -279,6 +309,8 @@ describe('v1.ClusterControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IDeleteClusterRequest = {};
             // Mock response
@@ -307,6 +339,8 @@ describe('v1.ClusterControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IDiagnoseClusterRequest = {};
             // Mock response
@@ -332,6 +366,8 @@ describe('v1.ClusterControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IDiagnoseClusterRequest = {};
             // Mock response
@@ -360,6 +396,8 @@ describe('v1.ClusterControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IListClustersRequest = {};
             // Mock response
@@ -382,6 +420,8 @@ describe('v1.ClusterControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IListClustersRequest = {};
             // Mock response
diff --git a/packages/google-cloud-dataproc/test/gapic-cluster_controller-v1beta2.ts b/packages/google-cloud-dataproc/test/gapic-cluster_controller-v1beta2.ts
index 7ea9fa4fa49..b9fc901d533 100644
--- a/packages/google-cloud-dataproc/test/gapic-cluster_controller-v1beta2.ts
+++ b/packages/google-cloud-dataproc/test/gapic-cluster_controller-v1beta2.ts
@@ -96,12 +96,30 @@ describe('v1beta2.ClusterControllerClient', () => {
         });
         assert(client);
     });
+    it('has initialize method and supports deferred initialization', async () => {
+        const client = new clustercontrollerModule.v1beta2.ClusterControllerClient({
+            credentials: { client_email: 'bogus', private_key: 'bogus' },
+            projectId: 'bogus',
+        });
+        assert.strictEqual(client.clusterControllerStub, undefined);
+        await client.initialize();
+        assert(client.clusterControllerStub);
+    });
+    it('has close method', () => {
+        const client = new clustercontrollerModule.v1beta2.ClusterControllerClient({
+            credentials: { client_email: 'bogus', private_key: 'bogus' },
+            projectId: 'bogus',
+        });
+        client.close();
+    });
     describe('getCluster', () => {
         it('invokes getCluster without error', done => {
             const client = new clustercontrollerModule.v1beta2.ClusterControllerClient({
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IGetClusterRequest = {};
             // Mock response
@@ -124,6 +142,8 @@ describe('v1beta2.ClusterControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IGetClusterRequest = {};
             // Mock response
@@ -148,6 +168,8 @@ describe('v1beta2.ClusterControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.ICreateClusterRequest = {};
             // Mock response
@@ -173,6 +195,8 @@ describe('v1beta2.ClusterControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.ICreateClusterRequest = {};
             // Mock response
@@ -201,6 +225,8 @@ describe('v1beta2.ClusterControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IUpdateClusterRequest = {};
             // Mock response
@@ -226,6 +252,8 @@ describe('v1beta2.ClusterControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IUpdateClusterRequest = {};
             // Mock response
@@ -254,6 +282,8 @@ describe('v1beta2.ClusterControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IDeleteClusterRequest = {};
             // Mock response
@@ -279,6 +309,8 @@ describe('v1beta2.ClusterControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IDeleteClusterRequest = {};
             // Mock response
@@ -307,6 +339,8 @@ describe('v1beta2.ClusterControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IDiagnoseClusterRequest = {};
             // Mock response
@@ -332,6 +366,8 @@ describe('v1beta2.ClusterControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IDiagnoseClusterRequest = {};
             // Mock response
@@ -360,6 +396,8 @@ describe('v1beta2.ClusterControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IListClustersRequest = {};
             // Mock response
@@ -382,6 +420,8 @@ describe('v1beta2.ClusterControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IListClustersRequest = {};
             // Mock response
diff --git a/packages/google-cloud-dataproc/test/gapic-job_controller-v1.ts b/packages/google-cloud-dataproc/test/gapic-job_controller-v1.ts
index cf2de18a43e..7b9746ccceb 100644
--- a/packages/google-cloud-dataproc/test/gapic-job_controller-v1.ts
+++ b/packages/google-cloud-dataproc/test/gapic-job_controller-v1.ts
@@ -78,12 +78,30 @@ describe('v1.JobControllerClient', () => {
         });
         assert(client);
     });
+    it('has initialize method and supports deferred initialization', async () => {
+        const client = new jobcontrollerModule.v1.JobControllerClient({
+            credentials: { client_email: 'bogus', private_key: 'bogus' },
+            projectId: 'bogus',
+        });
+        assert.strictEqual(client.jobControllerStub, undefined);
+        await client.initialize();
+        assert(client.jobControllerStub);
+    });
+    it('has close method', () => {
+        const client = new jobcontrollerModule.v1.JobControllerClient({
+            credentials: { client_email: 'bogus', private_key: 'bogus' },
+            projectId: 'bogus',
+        });
+        client.close();
+    });
     describe('submitJob', () => {
         it('invokes submitJob without error', done => {
             const client = new jobcontrollerModule.v1.JobControllerClient({
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.ISubmitJobRequest = {};
             // Mock response
@@ -106,6 +124,8 @@ describe('v1.JobControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.ISubmitJobRequest = {};
             // Mock response
@@ -130,6 +150,8 @@ describe('v1.JobControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IGetJobRequest = {};
             // Mock response
@@ -152,6 +174,8 @@ describe('v1.JobControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IGetJobRequest = {};
             // Mock response
@@ -176,6 +200,8 @@ describe('v1.JobControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IUpdateJobRequest = {};
             // Mock response
@@ -198,6 +224,8 @@ describe('v1.JobControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IUpdateJobRequest = {};
             // Mock response
@@ -222,6 +250,8 @@ describe('v1.JobControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.ICancelJobRequest = {};
             // Mock response
@@ -244,6 +274,8 @@ describe('v1.JobControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.ICancelJobRequest = {};
             // Mock response
@@ -268,6 +300,8 @@ describe('v1.JobControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IDeleteJobRequest = {};
             // Mock response
@@ -290,6 +324,8 @@ describe('v1.JobControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IDeleteJobRequest = {};
             // Mock response
@@ -314,6 +350,8 @@ describe('v1.JobControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IListJobsRequest = {};
             // Mock response
@@ -336,6 +374,8 @@ describe('v1.JobControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IListJobsRequest = {};
             // Mock response
diff --git a/packages/google-cloud-dataproc/test/gapic-job_controller-v1beta2.ts b/packages/google-cloud-dataproc/test/gapic-job_controller-v1beta2.ts
index 8b49868d539..11e0aa05c57 100644
--- a/packages/google-cloud-dataproc/test/gapic-job_controller-v1beta2.ts
+++ b/packages/google-cloud-dataproc/test/gapic-job_controller-v1beta2.ts
@@ -78,12 +78,30 @@ describe('v1beta2.JobControllerClient', () => {
         });
         assert(client);
     });
+    it('has initialize method and supports deferred initialization', async () => {
+        const client = new jobcontrollerModule.v1beta2.JobControllerClient({
+            credentials: { client_email: 'bogus', private_key: 'bogus' },
+            projectId: 'bogus',
+        });
+        assert.strictEqual(client.jobControllerStub, undefined);
+        await client.initialize();
+        assert(client.jobControllerStub);
+    });
+    it('has close method', () => {
+        const client = new jobcontrollerModule.v1beta2.JobControllerClient({
+            credentials: { client_email: 'bogus', private_key: 'bogus' },
+            projectId: 'bogus',
+        });
+        client.close();
+    });
     describe('submitJob', () => {
         it('invokes submitJob without error', done => {
             const client = new jobcontrollerModule.v1beta2.JobControllerClient({
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.ISubmitJobRequest = {};
             // Mock response
@@ -106,6 +124,8 @@ describe('v1beta2.JobControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.ISubmitJobRequest = {};
             // Mock response
@@ -130,6 +150,8 @@ describe('v1beta2.JobControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IGetJobRequest = {};
             // Mock response
@@ -152,6 +174,8 @@ describe('v1beta2.JobControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IGetJobRequest = {};
             // Mock response
@@ -176,6 +200,8 @@ describe('v1beta2.JobControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IUpdateJobRequest = {};
             // Mock response
@@ -198,6 +224,8 @@ describe('v1beta2.JobControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IUpdateJobRequest = {};
             // Mock response
@@ -222,6 +250,8 @@ describe('v1beta2.JobControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.ICancelJobRequest = {};
             // Mock response
@@ -244,6 +274,8 @@ describe('v1beta2.JobControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.ICancelJobRequest = {};
             // Mock response
@@ -268,6 +300,8 @@ describe('v1beta2.JobControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IDeleteJobRequest = {};
             // Mock response
@@ -290,6 +324,8 @@ describe('v1beta2.JobControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IDeleteJobRequest = {};
             // Mock response
@@ -314,6 +350,8 @@ describe('v1beta2.JobControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IListJobsRequest = {};
             // Mock response
@@ -336,6 +374,8 @@ describe('v1beta2.JobControllerClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IListJobsRequest = {};
             // Mock response
diff --git a/packages/google-cloud-dataproc/test/gapic-workflow_template_service-v1.ts b/packages/google-cloud-dataproc/test/gapic-workflow_template_service-v1.ts
index 63470a4d1ef..4b9ffa45a11 100644
--- a/packages/google-cloud-dataproc/test/gapic-workflow_template_service-v1.ts
+++ b/packages/google-cloud-dataproc/test/gapic-workflow_template_service-v1.ts
@@ -96,12 +96,30 @@ describe('v1.WorkflowTemplateServiceClient', () => {
         });
         assert(client);
     });
+    it('has initialize method and supports deferred initialization', async () => {
+        const client = new workflowtemplateserviceModule.v1.WorkflowTemplateServiceClient({
+            credentials: { client_email: 'bogus', private_key: 'bogus' },
+            projectId: 'bogus',
+        });
+        assert.strictEqual(client.workflowTemplateServiceStub, undefined);
+        await client.initialize();
+        assert(client.workflowTemplateServiceStub);
+    });
+    it('has close method', () => {
+        const client = new workflowtemplateserviceModule.v1.WorkflowTemplateServiceClient({
+            credentials: { client_email: 'bogus', private_key: 'bogus' },
+            projectId: 'bogus',
+        });
+        client.close();
+    });
     describe('createWorkflowTemplate', () => {
         it('invokes createWorkflowTemplate without error', done => {
             const client = new workflowtemplateserviceModule.v1.WorkflowTemplateServiceClient({
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.ICreateWorkflowTemplateRequest = {};
             request.parent = '';
@@ -125,6 +143,8 @@ describe('v1.WorkflowTemplateServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.ICreateWorkflowTemplateRequest = {};
             request.parent = '';
@@ -150,6 +170,8 @@ describe('v1.WorkflowTemplateServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IGetWorkflowTemplateRequest = {};
             request.name = '';
@@ -173,6 +195,8 @@ describe('v1.WorkflowTemplateServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IGetWorkflowTemplateRequest = {};
             request.name = '';
@@ -198,6 +222,8 @@ describe('v1.WorkflowTemplateServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IUpdateWorkflowTemplateRequest = {};
             request.template = {};
@@ -222,6 +248,8 @@ describe('v1.WorkflowTemplateServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IUpdateWorkflowTemplateRequest = {};
             request.template = {};
@@ -248,6 +276,8 @@ describe('v1.WorkflowTemplateServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IDeleteWorkflowTemplateRequest = {};
             request.name = '';
@@ -271,6 +301,8 @@ describe('v1.WorkflowTemplateServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IDeleteWorkflowTemplateRequest = {};
             request.name = '';
@@ -296,6 +328,8 @@ describe('v1.WorkflowTemplateServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IInstantiateWorkflowTemplateRequest = {};
             request.name = '';
@@ -322,6 +356,8 @@ describe('v1.WorkflowTemplateServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IInstantiateWorkflowTemplateRequest = {};
             request.name = '';
@@ -351,6 +387,8 @@ describe('v1.WorkflowTemplateServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IInstantiateInlineWorkflowTemplateRequest = {};
             request.parent = '';
@@ -377,6 +415,8 @@ describe('v1.WorkflowTemplateServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IInstantiateInlineWorkflowTemplateRequest = {};
             request.parent = '';
@@ -406,6 +446,8 @@ describe('v1.WorkflowTemplateServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IListWorkflowTemplatesRequest = {};
             request.parent = '';
@@ -429,6 +471,8 @@ describe('v1.WorkflowTemplateServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1.IListWorkflowTemplatesRequest = {};
             request.parent = '';
diff --git a/packages/google-cloud-dataproc/test/gapic-workflow_template_service-v1beta2.ts b/packages/google-cloud-dataproc/test/gapic-workflow_template_service-v1beta2.ts
index 0514cdbfce5..7019065feda 100644
--- a/packages/google-cloud-dataproc/test/gapic-workflow_template_service-v1beta2.ts
+++ b/packages/google-cloud-dataproc/test/gapic-workflow_template_service-v1beta2.ts
@@ -96,12 +96,30 @@ describe('v1beta2.WorkflowTemplateServiceClient', () => {
         });
         assert(client);
     });
+    it('has initialize method and supports deferred initialization', async () => {
+        const client = new workflowtemplateserviceModule.v1beta2.WorkflowTemplateServiceClient({
+            credentials: { client_email: 'bogus', private_key: 'bogus' },
+            projectId: 'bogus',
+        });
+        assert.strictEqual(client.workflowTemplateServiceStub, undefined);
+        await client.initialize();
+        assert(client.workflowTemplateServiceStub);
+    });
+    it('has close method', () => {
+        const client = new workflowtemplateserviceModule.v1beta2.WorkflowTemplateServiceClient({
+            credentials: { client_email: 'bogus', private_key: 'bogus' },
+            projectId: 'bogus',
+        });
+        client.close();
+    });
     describe('createWorkflowTemplate', () => {
         it('invokes createWorkflowTemplate without error', done => {
             const client = new workflowtemplateserviceModule.v1beta2.WorkflowTemplateServiceClient({
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.ICreateWorkflowTemplateRequest = {};
             request.parent = '';
@@ -125,6 +143,8 @@ describe('v1beta2.WorkflowTemplateServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.ICreateWorkflowTemplateRequest = {};
             request.parent = '';
@@ -150,6 +170,8 @@ describe('v1beta2.WorkflowTemplateServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IGetWorkflowTemplateRequest = {};
             request.name = '';
@@ -173,6 +195,8 @@ describe('v1beta2.WorkflowTemplateServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IGetWorkflowTemplateRequest = {};
             request.name = '';
@@ -198,6 +222,8 @@ describe('v1beta2.WorkflowTemplateServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IUpdateWorkflowTemplateRequest = {};
             request.template = {};
@@ -222,6 +248,8 @@ describe('v1beta2.WorkflowTemplateServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IUpdateWorkflowTemplateRequest = {};
             request.template = {};
@@ -248,6 +276,8 @@ describe('v1beta2.WorkflowTemplateServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IDeleteWorkflowTemplateRequest = {};
             request.name = '';
@@ -271,6 +301,8 @@ describe('v1beta2.WorkflowTemplateServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IDeleteWorkflowTemplateRequest = {};
             request.name = '';
@@ -296,6 +328,8 @@ describe('v1beta2.WorkflowTemplateServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IInstantiateWorkflowTemplateRequest = {};
             request.name = '';
@@ -322,6 +356,8 @@ describe('v1beta2.WorkflowTemplateServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IInstantiateWorkflowTemplateRequest = {};
             request.name = '';
@@ -351,6 +387,8 @@ describe('v1beta2.WorkflowTemplateServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IInstantiateInlineWorkflowTemplateRequest = {};
             request.parent = '';
@@ -377,6 +415,8 @@ describe('v1beta2.WorkflowTemplateServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IInstantiateInlineWorkflowTemplateRequest = {};
             request.parent = '';
@@ -406,6 +446,8 @@ describe('v1beta2.WorkflowTemplateServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IListWorkflowTemplatesRequest = {};
             request.parent = '';
@@ -429,6 +471,8 @@ describe('v1beta2.WorkflowTemplateServiceClient', () => {
                 credentials: {client_email: 'bogus', private_key: 'bogus'},
                 projectId: 'bogus',
             });
+            // Initialize client before mocking
+            client.initialize();
             // Mock request
             const request: protosTypes.google.cloud.dataproc.v1beta2.IListWorkflowTemplatesRequest = {};
             request.parent = '';