diff --git a/packages/google-cloud-securitycenter/src/v1/security_center_client.ts b/packages/google-cloud-securitycenter/src/v1/security_center_client.ts
index b77b522f2e1..c3834524b57 100644
--- a/packages/google-cloud-securitycenter/src/v1/security_center_client.ts
+++ b/packages/google-cloud-securitycenter/src/v1/security_center_client.ts
@@ -45,9 +45,14 @@ export class SecurityCenterClient {
   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;
-  securityCenterStub: Promise<{[name: string]: Function}>;
+  securityCenterStub?: Promise<{[name: string]: Function}>;
 
   /**
    * Construct an instance of SecurityCenterClient.
@@ -71,8 +76,6 @@ export class SecurityCenterClient {
    *     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.
    */
@@ -102,25 +105,28 @@ export class SecurityCenterClient {
     // 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 SecurityCenterClient).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/${gaxModule.version}`, `gapic/${version}`];
+    const clientHeader = [`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}`);
@@ -136,7 +142,7 @@ export class SecurityCenterClient {
       'protos',
       'protos.json'
     );
-    const protos = gaxGrpc.loadProto(
+    this._protos = this._gaxGrpc.loadProto(
       opts.fallback ? require('../../protos/protos.json') : nodejsProtoPath
     );
 
@@ -144,28 +150,28 @@ export class SecurityCenterClient {
     // identifiers to uniquely identify resources within the API.
     // Create useful helper objects for these.
     this._pathTemplates = {
-      assetPathTemplate: new gaxModule.PathTemplate(
+      assetPathTemplate: new this._gaxModule.PathTemplate(
         'organizations/{organization}/assets/{asset}'
       ),
-      findingPathTemplate: new gaxModule.PathTemplate(
+      findingPathTemplate: new this._gaxModule.PathTemplate(
         'organizations/{organization}/sources/{source}/findings/{finding}'
       ),
-      notificationConfigPathTemplate: new gaxModule.PathTemplate(
+      notificationConfigPathTemplate: new this._gaxModule.PathTemplate(
         'organizations/{organization}/notificationConfigs/{notification_config}'
       ),
-      organizationPathTemplate: new gaxModule.PathTemplate(
+      organizationPathTemplate: new this._gaxModule.PathTemplate(
         'organizations/{organization}'
       ),
-      organizationAssetPathTemplate: new gaxModule.PathTemplate(
+      organizationAssetPathTemplate: new this._gaxModule.PathTemplate(
         'organizations/{organization}/assets/{asset}/securityMarks'
       ),
-      organizationSettingsPathTemplate: new gaxModule.PathTemplate(
+      organizationSettingsPathTemplate: new this._gaxModule.PathTemplate(
         'organizations/{organization}/organizationSettings'
       ),
-      organizationSourceFindingPathTemplate: new gaxModule.PathTemplate(
+      organizationSourceFindingPathTemplate: new this._gaxModule.PathTemplate(
         'organizations/{organization}/sources/{source}/findings/{finding}/securityMarks'
       ),
-      sourcePathTemplate: new gaxModule.PathTemplate(
+      sourcePathTemplate: new this._gaxModule.PathTemplate(
         'organizations/{organization}/sources/{source}'
       ),
     };
@@ -174,32 +180,32 @@ export class SecurityCenterClient {
     // (e.g. 50 results at a time, with tokens to get subsequent
     // pages). Denote the keys used for pagination and results.
     this._descriptors.page = {
-      groupAssets: new gaxModule.PageDescriptor(
+      groupAssets: new this._gaxModule.PageDescriptor(
         'pageToken',
         'nextPageToken',
         'groupByResults'
       ),
-      groupFindings: new gaxModule.PageDescriptor(
+      groupFindings: new this._gaxModule.PageDescriptor(
         'pageToken',
         'nextPageToken',
         'groupByResults'
       ),
-      listAssets: new gaxModule.PageDescriptor(
+      listAssets: new this._gaxModule.PageDescriptor(
         'pageToken',
         'nextPageToken',
         'listAssetsResults'
       ),
-      listFindings: new gaxModule.PageDescriptor(
+      listFindings: new this._gaxModule.PageDescriptor(
         'pageToken',
         'nextPageToken',
         'listFindingsResults'
       ),
-      listNotificationConfigs: new gaxModule.PageDescriptor(
+      listNotificationConfigs: new this._gaxModule.PageDescriptor(
         'pageToken',
         'nextPageToken',
         'notificationConfigs'
       ),
-      listSources: new gaxModule.PageDescriptor(
+      listSources: new this._gaxModule.PageDescriptor(
         'pageToken',
         'nextPageToken',
         'sources'
@@ -210,13 +216,15 @@ export class SecurityCenterClient {
     // 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
+    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 runAssetDiscoveryResponse = protoFilesRoot.lookup(
@@ -227,7 +235,7 @@ export class SecurityCenterClient {
     ) as gax.protobuf.Type;
 
     this._descriptors.longrunning = {
-      runAssetDiscovery: new gaxModule.LongrunningDescriptor(
+      runAssetDiscovery: new this._gaxModule.LongrunningDescriptor(
         this.operationsClient,
         runAssetDiscoveryResponse.decode.bind(runAssetDiscoveryResponse),
         runAssetDiscoveryMetadata.decode.bind(runAssetDiscoveryMetadata)
@@ -235,7 +243,7 @@ export class SecurityCenterClient {
     };
 
     // Put together the default options sent with requests.
-    const defaults = gaxGrpc.constructSettings(
+    this._defaults = this._gaxGrpc.constructSettings(
       'google.cloud.securitycenter.v1.SecurityCenter',
       gapicConfig as gax.ClientConfig,
       opts.clientConfig || {},
@@ -246,17 +254,35 @@ export class SecurityCenterClient {
     // 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.securityCenterStub) {
+      return this.securityCenterStub;
+    }
 
     // Put together the "service stub" for
     // google.cloud.securitycenter.v1.SecurityCenter.
-    this.securityCenterStub = gaxGrpc.createStub(
-      opts.fallback
-        ? (protos as protobuf.Root).lookupService(
+    this.securityCenterStub = this._gaxGrpc.createStub(
+      this._opts.fallback
+        ? (this._protos as protobuf.Root).lookupService(
             'google.cloud.securitycenter.v1.SecurityCenter'
           )
         : // tslint:disable-next-line no-any
-          (protos as any).google.cloud.securitycenter.v1.SecurityCenter,
-      opts
+          (this._protos as any).google.cloud.securitycenter.v1.SecurityCenter,
+      this._opts
     ) as Promise<{[method: string]: Function}>;
 
     // Iterate over each of the methods that the service provides
@@ -300,9 +326,9 @@ export class SecurityCenterClient {
         }
       );
 
-      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]
@@ -316,6 +342,8 @@ export class SecurityCenterClient {
         return apiCall(argument, callOptions, callback);
       };
     }
+
+    return this.securityCenterStub;
   }
 
   /**
@@ -450,6 +478,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       parent: request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.createSource(request, options, callback);
   }
   createFinding(
@@ -539,6 +568,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       parent: request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.createFinding(request, options, callback);
   }
   createNotificationConfig(
@@ -629,6 +659,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       parent: request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.createNotificationConfig(
       request,
       options,
@@ -714,6 +745,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       name: request.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.deleteNotificationConfig(
       request,
       options,
@@ -787,6 +819,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       resource: request.resource || '',
     });
+    this.initialize();
     return this._innerApiCalls.getIamPolicy(request, options, callback);
   }
   getNotificationConfig(
@@ -868,6 +901,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       name: request.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.getNotificationConfig(
       request,
       options,
@@ -953,6 +987,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       name: request.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.getOrganizationSettings(
       request,
       options,
@@ -1030,6 +1065,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       name: request.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.getSource(request, options, callback);
   }
   setFindingState(
@@ -1117,6 +1153,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       name: request.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.setFindingState(request, options, callback);
   }
   setIamPolicy(
@@ -1186,6 +1223,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       resource: request.resource || '',
     });
+    this.initialize();
     return this._innerApiCalls.setIamPolicy(request, options, callback);
   }
   testIamPermissions(
@@ -1255,6 +1293,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       resource: request.resource || '',
     });
+    this.initialize();
     return this._innerApiCalls.testIamPermissions(request, options, callback);
   }
   updateFinding(
@@ -1349,6 +1388,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       'finding.name': request.finding!.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.updateFinding(request, options, callback);
   }
   updateNotificationConfig(
@@ -1434,6 +1474,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       'notification_config.name': request.notificationConfig!.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.updateNotificationConfig(
       request,
       options,
@@ -1522,6 +1563,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       'organization_settings.name': request.organizationSettings!.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.updateOrganizationSettings(
       request,
       options,
@@ -1610,6 +1652,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       'source.name': request.source!.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.updateSource(request, options, callback);
   }
   updateSecurityMarks(
@@ -1700,6 +1743,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       'security_marks.name': request.securityMarks!.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.updateSecurityMarks(request, options, callback);
   }
 
@@ -1793,6 +1837,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       parent: request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.runAssetDiscovery(request, options, callback);
   }
   groupAssets(
@@ -1994,6 +2039,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       parent: request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.groupAssets(request, options, callback);
   }
 
@@ -2150,6 +2196,7 @@ export class SecurityCenterClient {
       parent: request.parent || '',
     });
     const callSettings = new gax.CallSettings(options);
+    this.initialize();
     return this._descriptors.page.groupAssets.createStream(
       this._innerApiCalls.groupAssets as gax.GaxCall,
       request,
@@ -2348,6 +2395,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       parent: request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.groupFindings(request, options, callback);
   }
 
@@ -2494,6 +2542,7 @@ export class SecurityCenterClient {
       parent: request.parent || '',
     });
     const callSettings = new gax.CallSettings(options);
+    this.initialize();
     return this._descriptors.page.groupFindings.createStream(
       this._innerApiCalls.groupFindings as gax.GaxCall,
       request,
@@ -2701,6 +2750,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       parent: request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.listAssets(request, options, callback);
   }
 
@@ -2860,6 +2910,7 @@ export class SecurityCenterClient {
       parent: request.parent || '',
     });
     const callSettings = new gax.CallSettings(options);
+    this.initialize();
     return this._descriptors.page.listAssets.createStream(
       this._innerApiCalls.listAssets as gax.GaxCall,
       request,
@@ -3062,6 +3113,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       parent: request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.listFindings(request, options, callback);
   }
 
@@ -3213,6 +3265,7 @@ export class SecurityCenterClient {
       parent: request.parent || '',
     });
     const callSettings = new gax.CallSettings(options);
+    this.initialize();
     return this._descriptors.page.listFindings.createStream(
       this._innerApiCalls.listFindings as gax.GaxCall,
       request,
@@ -3308,6 +3361,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       parent: request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.listNotificationConfigs(
       request,
       options,
@@ -3359,6 +3413,7 @@ export class SecurityCenterClient {
       parent: request.parent || '',
     });
     const callSettings = new gax.CallSettings(options);
+    this.initialize();
     return this._descriptors.page.listNotificationConfigs.createStream(
       this._innerApiCalls.listNotificationConfigs as gax.GaxCall,
       request,
@@ -3454,6 +3509,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       parent: request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.listSources(request, options, callback);
   }
 
@@ -3501,6 +3557,7 @@ export class SecurityCenterClient {
       parent: request.parent || '',
     });
     const callSettings = new gax.CallSettings(options);
+    this.initialize();
     return this._descriptors.page.listSources.createStream(
       this._innerApiCalls.listSources as gax.GaxCall,
       request,
@@ -3838,8 +3895,9 @@ export class SecurityCenterClient {
    * The client will no longer be usable and all future behavior is undefined.
    */
   close(): Promise<void> {
+    this.initialize();
     if (!this._terminated) {
-      return this.securityCenterStub.then(stub => {
+      return this.securityCenterStub!.then(stub => {
         this._terminated = true;
         stub.close();
       });
diff --git a/packages/google-cloud-securitycenter/src/v1beta1/security_center_client.ts b/packages/google-cloud-securitycenter/src/v1beta1/security_center_client.ts
index 7833c90ee49..2fb75e362cc 100644
--- a/packages/google-cloud-securitycenter/src/v1beta1/security_center_client.ts
+++ b/packages/google-cloud-securitycenter/src/v1beta1/security_center_client.ts
@@ -45,9 +45,14 @@ export class SecurityCenterClient {
   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;
-  securityCenterStub: Promise<{[name: string]: Function}>;
+  securityCenterStub?: Promise<{[name: string]: Function}>;
 
   /**
    * Construct an instance of SecurityCenterClient.
@@ -71,8 +76,6 @@ export class SecurityCenterClient {
    *     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.
    */
@@ -102,25 +105,28 @@ export class SecurityCenterClient {
     // 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 SecurityCenterClient).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/${gaxModule.version}`, `gapic/${version}`];
+    const clientHeader = [`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}`);
@@ -136,7 +142,7 @@ export class SecurityCenterClient {
       'protos',
       'protos.json'
     );
-    const protos = gaxGrpc.loadProto(
+    this._protos = this._gaxGrpc.loadProto(
       opts.fallback ? require('../../protos/protos.json') : nodejsProtoPath
     );
 
@@ -144,22 +150,22 @@ export class SecurityCenterClient {
     // identifiers to uniquely identify resources within the API.
     // Create useful helper objects for these.
     this._pathTemplates = {
-      findingPathTemplate: new gaxModule.PathTemplate(
+      findingPathTemplate: new this._gaxModule.PathTemplate(
         'organizations/{organization}/sources/{source}/findings/{finding}'
       ),
-      organizationPathTemplate: new gaxModule.PathTemplate(
+      organizationPathTemplate: new this._gaxModule.PathTemplate(
         'organizations/{organization}'
       ),
-      organizationAssetPathTemplate: new gaxModule.PathTemplate(
+      organizationAssetPathTemplate: new this._gaxModule.PathTemplate(
         'organizations/{organization}/assets/{asset}/securityMarks'
       ),
-      organizationSettingsPathTemplate: new gaxModule.PathTemplate(
+      organizationSettingsPathTemplate: new this._gaxModule.PathTemplate(
         'organizations/{organization}/organizationSettings'
       ),
-      organizationSourceFindingPathTemplate: new gaxModule.PathTemplate(
+      organizationSourceFindingPathTemplate: new this._gaxModule.PathTemplate(
         'organizations/{organization}/sources/{source}/findings/{finding}/securityMarks'
       ),
-      sourcePathTemplate: new gaxModule.PathTemplate(
+      sourcePathTemplate: new this._gaxModule.PathTemplate(
         'organizations/{organization}/sources/{source}'
       ),
     };
@@ -168,27 +174,27 @@ export class SecurityCenterClient {
     // (e.g. 50 results at a time, with tokens to get subsequent
     // pages). Denote the keys used for pagination and results.
     this._descriptors.page = {
-      groupAssets: new gaxModule.PageDescriptor(
+      groupAssets: new this._gaxModule.PageDescriptor(
         'pageToken',
         'nextPageToken',
         'groupByResults'
       ),
-      groupFindings: new gaxModule.PageDescriptor(
+      groupFindings: new this._gaxModule.PageDescriptor(
         'pageToken',
         'nextPageToken',
         'groupByResults'
       ),
-      listAssets: new gaxModule.PageDescriptor(
+      listAssets: new this._gaxModule.PageDescriptor(
         'pageToken',
         'nextPageToken',
         'listAssetsResults'
       ),
-      listFindings: new gaxModule.PageDescriptor(
+      listFindings: new this._gaxModule.PageDescriptor(
         'pageToken',
         'nextPageToken',
         'findings'
       ),
-      listSources: new gaxModule.PageDescriptor(
+      listSources: new this._gaxModule.PageDescriptor(
         'pageToken',
         'nextPageToken',
         'sources'
@@ -199,13 +205,15 @@ export class SecurityCenterClient {
     // 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
+    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 runAssetDiscoveryResponse = protoFilesRoot.lookup(
@@ -216,7 +224,7 @@ export class SecurityCenterClient {
     ) as gax.protobuf.Type;
 
     this._descriptors.longrunning = {
-      runAssetDiscovery: new gaxModule.LongrunningDescriptor(
+      runAssetDiscovery: new this._gaxModule.LongrunningDescriptor(
         this.operationsClient,
         runAssetDiscoveryResponse.decode.bind(runAssetDiscoveryResponse),
         runAssetDiscoveryMetadata.decode.bind(runAssetDiscoveryMetadata)
@@ -224,7 +232,7 @@ export class SecurityCenterClient {
     };
 
     // Put together the default options sent with requests.
-    const defaults = gaxGrpc.constructSettings(
+    this._defaults = this._gaxGrpc.constructSettings(
       'google.cloud.securitycenter.v1beta1.SecurityCenter',
       gapicConfig as gax.ClientConfig,
       opts.clientConfig || {},
@@ -235,17 +243,36 @@ export class SecurityCenterClient {
     // 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.securityCenterStub) {
+      return this.securityCenterStub;
+    }
 
     // Put together the "service stub" for
     // google.cloud.securitycenter.v1beta1.SecurityCenter.
-    this.securityCenterStub = gaxGrpc.createStub(
-      opts.fallback
-        ? (protos as protobuf.Root).lookupService(
+    this.securityCenterStub = this._gaxGrpc.createStub(
+      this._opts.fallback
+        ? (this._protos as protobuf.Root).lookupService(
             'google.cloud.securitycenter.v1beta1.SecurityCenter'
           )
         : // tslint:disable-next-line no-any
-          (protos as any).google.cloud.securitycenter.v1beta1.SecurityCenter,
-      opts
+          (this._protos as any).google.cloud.securitycenter.v1beta1
+            .SecurityCenter,
+      this._opts
     ) as Promise<{[method: string]: Function}>;
 
     // Iterate over each of the methods that the service provides
@@ -284,9 +311,9 @@ export class SecurityCenterClient {
         }
       );
 
-      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]
@@ -300,6 +327,8 @@ export class SecurityCenterClient {
         return apiCall(argument, callOptions, callback);
       };
     }
+
+    return this.securityCenterStub;
   }
 
   /**
@@ -434,6 +463,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       parent: request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.createSource(request, options, callback);
   }
   createFinding(
@@ -523,6 +553,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       parent: request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.createFinding(request, options, callback);
   }
   getIamPolicy(
@@ -592,6 +623,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       resource: request.resource || '',
     });
+    this.initialize();
     return this._innerApiCalls.getIamPolicy(request, options, callback);
   }
   getOrganizationSettings(
@@ -673,6 +705,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       name: request.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.getOrganizationSettings(
       request,
       options,
@@ -758,6 +791,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       name: request.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.getSource(request, options, callback);
   }
   setFindingState(
@@ -845,6 +879,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       name: request.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.setFindingState(request, options, callback);
   }
   setIamPolicy(
@@ -914,6 +949,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       resource: request.resource || '',
     });
+    this.initialize();
     return this._innerApiCalls.setIamPolicy(request, options, callback);
   }
   testIamPermissions(
@@ -983,6 +1019,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       resource: request.resource || '',
     });
+    this.initialize();
     return this._innerApiCalls.testIamPermissions(request, options, callback);
   }
   updateFinding(
@@ -1072,6 +1109,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       'finding.name': request.finding!.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.updateFinding(request, options, callback);
   }
   updateOrganizationSettings(
@@ -1154,6 +1192,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       'organization_settings.name': request.organizationSettings!.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.updateOrganizationSettings(
       request,
       options,
@@ -1240,6 +1279,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       'source.name': request.source!.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.updateSource(request, options, callback);
   }
   updateSecurityMarks(
@@ -1324,6 +1364,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       'security_marks.name': request.securityMarks!.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.updateSecurityMarks(request, options, callback);
   }
 
@@ -1417,6 +1458,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       parent: request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.runAssetDiscovery(request, options, callback);
   }
   groupAssets(
@@ -1579,6 +1621,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       parent: request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.groupAssets(request, options, callback);
   }
 
@@ -1696,6 +1739,7 @@ export class SecurityCenterClient {
       parent: request.parent || '',
     });
     const callSettings = new gax.CallSettings(options);
+    this.initialize();
     return this._descriptors.page.groupAssets.createStream(
       this._innerApiCalls.groupAssets as gax.GaxCall,
       request,
@@ -1840,6 +1884,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       parent: request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.groupFindings(request, options, callback);
   }
 
@@ -1932,6 +1977,7 @@ export class SecurityCenterClient {
       parent: request.parent || '',
     });
     const callSettings = new gax.CallSettings(options);
+    this.initialize();
     return this._descriptors.page.groupFindings.createStream(
       this._innerApiCalls.groupFindings as gax.GaxCall,
       request,
@@ -2097,6 +2143,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       parent: request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.listAssets(request, options, callback);
   }
 
@@ -2214,6 +2261,7 @@ export class SecurityCenterClient {
       parent: request.parent || '',
     });
     const callSettings = new gax.CallSettings(options);
+    this.initialize();
     return this._descriptors.page.listAssets.createStream(
       this._innerApiCalls.listAssets as gax.GaxCall,
       request,
@@ -2357,6 +2405,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       parent: request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.listFindings(request, options, callback);
   }
 
@@ -2449,6 +2498,7 @@ export class SecurityCenterClient {
       parent: request.parent || '',
     });
     const callSettings = new gax.CallSettings(options);
+    this.initialize();
     return this._descriptors.page.listFindings.createStream(
       this._innerApiCalls.listFindings as gax.GaxCall,
       request,
@@ -2544,6 +2594,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       parent: request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.listSources(request, options, callback);
   }
 
@@ -2591,6 +2642,7 @@ export class SecurityCenterClient {
       parent: request.parent || '',
     });
     const callSettings = new gax.CallSettings(options);
+    this.initialize();
     return this._descriptors.page.listSources.createStream(
       this._innerApiCalls.listSources as gax.GaxCall,
       request,
@@ -2850,8 +2902,9 @@ export class SecurityCenterClient {
    * The client will no longer be usable and all future behavior is undefined.
    */
   close(): Promise<void> {
+    this.initialize();
     if (!this._terminated) {
-      return this.securityCenterStub.then(stub => {
+      return this.securityCenterStub!.then(stub => {
         this._terminated = true;
         stub.close();
       });
diff --git a/packages/google-cloud-securitycenter/src/v1p1beta1/security_center_client.ts b/packages/google-cloud-securitycenter/src/v1p1beta1/security_center_client.ts
index 5c074f05680..0f4069e5be2 100644
--- a/packages/google-cloud-securitycenter/src/v1p1beta1/security_center_client.ts
+++ b/packages/google-cloud-securitycenter/src/v1p1beta1/security_center_client.ts
@@ -45,9 +45,14 @@ export class SecurityCenterClient {
   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;
-  securityCenterStub: Promise<{[name: string]: Function}>;
+  securityCenterStub?: Promise<{[name: string]: Function}>;
 
   /**
    * Construct an instance of SecurityCenterClient.
@@ -71,8 +76,6 @@ export class SecurityCenterClient {
    *     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.
    */
@@ -102,25 +105,28 @@ export class SecurityCenterClient {
     // 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 SecurityCenterClient).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/${gaxModule.version}`, `gapic/${version}`];
+    const clientHeader = [`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}`);
@@ -136,7 +142,7 @@ export class SecurityCenterClient {
       'protos',
       'protos.json'
     );
-    const protos = gaxGrpc.loadProto(
+    this._protos = this._gaxGrpc.loadProto(
       opts.fallback ? require('../../protos/protos.json') : nodejsProtoPath
     );
 
@@ -144,28 +150,28 @@ export class SecurityCenterClient {
     // identifiers to uniquely identify resources within the API.
     // Create useful helper objects for these.
     this._pathTemplates = {
-      assetPathTemplate: new gaxModule.PathTemplate(
+      assetPathTemplate: new this._gaxModule.PathTemplate(
         'organizations/{organization}/assets/{asset}'
       ),
-      findingPathTemplate: new gaxModule.PathTemplate(
+      findingPathTemplate: new this._gaxModule.PathTemplate(
         'organizations/{organization}/sources/{source}/findings/{finding}'
       ),
-      notificationConfigPathTemplate: new gaxModule.PathTemplate(
+      notificationConfigPathTemplate: new this._gaxModule.PathTemplate(
         'organizations/{organization}/notificationConfigs/{notification_config}'
       ),
-      organizationPathTemplate: new gaxModule.PathTemplate(
+      organizationPathTemplate: new this._gaxModule.PathTemplate(
         'organizations/{organization}'
       ),
-      organizationAssetPathTemplate: new gaxModule.PathTemplate(
+      organizationAssetPathTemplate: new this._gaxModule.PathTemplate(
         'organizations/{organization}/assets/{asset}/securityMarks'
       ),
-      organizationSettingsPathTemplate: new gaxModule.PathTemplate(
+      organizationSettingsPathTemplate: new this._gaxModule.PathTemplate(
         'organizations/{organization}/organizationSettings'
       ),
-      organizationSourceFindingPathTemplate: new gaxModule.PathTemplate(
+      organizationSourceFindingPathTemplate: new this._gaxModule.PathTemplate(
         'organizations/{organization}/sources/{source}/findings/{finding}/securityMarks'
       ),
-      sourcePathTemplate: new gaxModule.PathTemplate(
+      sourcePathTemplate: new this._gaxModule.PathTemplate(
         'organizations/{organization}/sources/{source}'
       ),
     };
@@ -174,32 +180,32 @@ export class SecurityCenterClient {
     // (e.g. 50 results at a time, with tokens to get subsequent
     // pages). Denote the keys used for pagination and results.
     this._descriptors.page = {
-      groupAssets: new gaxModule.PageDescriptor(
+      groupAssets: new this._gaxModule.PageDescriptor(
         'pageToken',
         'nextPageToken',
         'groupByResults'
       ),
-      groupFindings: new gaxModule.PageDescriptor(
+      groupFindings: new this._gaxModule.PageDescriptor(
         'pageToken',
         'nextPageToken',
         'groupByResults'
       ),
-      listAssets: new gaxModule.PageDescriptor(
+      listAssets: new this._gaxModule.PageDescriptor(
         'pageToken',
         'nextPageToken',
         'listAssetsResults'
       ),
-      listFindings: new gaxModule.PageDescriptor(
+      listFindings: new this._gaxModule.PageDescriptor(
         'pageToken',
         'nextPageToken',
         'listFindingsResults'
       ),
-      listNotificationConfigs: new gaxModule.PageDescriptor(
+      listNotificationConfigs: new this._gaxModule.PageDescriptor(
         'pageToken',
         'nextPageToken',
         'notificationConfigs'
       ),
-      listSources: new gaxModule.PageDescriptor(
+      listSources: new this._gaxModule.PageDescriptor(
         'pageToken',
         'nextPageToken',
         'sources'
@@ -210,13 +216,15 @@ export class SecurityCenterClient {
     // 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
+    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 runAssetDiscoveryResponse = protoFilesRoot.lookup(
@@ -227,7 +235,7 @@ export class SecurityCenterClient {
     ) as gax.protobuf.Type;
 
     this._descriptors.longrunning = {
-      runAssetDiscovery: new gaxModule.LongrunningDescriptor(
+      runAssetDiscovery: new this._gaxModule.LongrunningDescriptor(
         this.operationsClient,
         runAssetDiscoveryResponse.decode.bind(runAssetDiscoveryResponse),
         runAssetDiscoveryMetadata.decode.bind(runAssetDiscoveryMetadata)
@@ -235,7 +243,7 @@ export class SecurityCenterClient {
     };
 
     // Put together the default options sent with requests.
-    const defaults = gaxGrpc.constructSettings(
+    this._defaults = this._gaxGrpc.constructSettings(
       'google.cloud.securitycenter.v1p1beta1.SecurityCenter',
       gapicConfig as gax.ClientConfig,
       opts.clientConfig || {},
@@ -246,17 +254,36 @@ export class SecurityCenterClient {
     // 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.securityCenterStub) {
+      return this.securityCenterStub;
+    }
 
     // Put together the "service stub" for
     // google.cloud.securitycenter.v1p1beta1.SecurityCenter.
-    this.securityCenterStub = gaxGrpc.createStub(
-      opts.fallback
-        ? (protos as protobuf.Root).lookupService(
+    this.securityCenterStub = this._gaxGrpc.createStub(
+      this._opts.fallback
+        ? (this._protos as protobuf.Root).lookupService(
             'google.cloud.securitycenter.v1p1beta1.SecurityCenter'
           )
         : // tslint:disable-next-line no-any
-          (protos as any).google.cloud.securitycenter.v1p1beta1.SecurityCenter,
-      opts
+          (this._protos as any).google.cloud.securitycenter.v1p1beta1
+            .SecurityCenter,
+      this._opts
     ) as Promise<{[method: string]: Function}>;
 
     // Iterate over each of the methods that the service provides
@@ -300,9 +327,9 @@ export class SecurityCenterClient {
         }
       );
 
-      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]
@@ -316,6 +343,8 @@ export class SecurityCenterClient {
         return apiCall(argument, callOptions, callback);
       };
     }
+
+    return this.securityCenterStub;
   }
 
   /**
@@ -450,6 +479,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       parent: request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.createSource(request, options, callback);
   }
   createFinding(
@@ -540,6 +570,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       parent: request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.createFinding(request, options, callback);
   }
   createNotificationConfig(
@@ -630,6 +661,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       parent: request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.createNotificationConfig(
       request,
       options,
@@ -715,6 +747,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       name: request.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.deleteNotificationConfig(
       request,
       options,
@@ -788,6 +821,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       resource: request.resource || '',
     });
+    this.initialize();
     return this._innerApiCalls.getIamPolicy(request, options, callback);
   }
   getNotificationConfig(
@@ -869,6 +903,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       name: request.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.getNotificationConfig(
       request,
       options,
@@ -954,6 +989,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       name: request.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.getOrganizationSettings(
       request,
       options,
@@ -1039,6 +1075,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       name: request.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.getSource(request, options, callback);
   }
   setFindingState(
@@ -1127,6 +1164,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       name: request.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.setFindingState(request, options, callback);
   }
   setIamPolicy(
@@ -1196,6 +1234,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       resource: request.resource || '',
     });
+    this.initialize();
     return this._innerApiCalls.setIamPolicy(request, options, callback);
   }
   testIamPermissions(
@@ -1265,6 +1304,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       resource: request.resource || '',
     });
+    this.initialize();
     return this._innerApiCalls.testIamPermissions(request, options, callback);
   }
   updateFinding(
@@ -1360,6 +1400,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       'finding.name': request.finding!.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.updateFinding(request, options, callback);
   }
   updateNotificationConfig(
@@ -1444,6 +1485,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       'notification_config.name': request.notificationConfig!.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.updateNotificationConfig(
       request,
       options,
@@ -1532,6 +1574,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       'organization_settings.name': request.organizationSettings!.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.updateOrganizationSettings(
       request,
       options,
@@ -1620,6 +1663,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       'source.name': request.source!.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.updateSource(request, options, callback);
   }
   updateSecurityMarks(
@@ -1710,6 +1754,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       'security_marks.name': request.securityMarks!.name || '',
     });
+    this.initialize();
     return this._innerApiCalls.updateSecurityMarks(request, options, callback);
   }
 
@@ -1803,6 +1848,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       parent: request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.runAssetDiscovery(request, options, callback);
   }
   groupAssets(
@@ -2008,6 +2054,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       parent: request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.groupAssets(request, options, callback);
   }
 
@@ -2168,6 +2215,7 @@ export class SecurityCenterClient {
       parent: request.parent || '',
     });
     const callSettings = new gax.CallSettings(options);
+    this.initialize();
     return this._descriptors.page.groupAssets.createStream(
       this._innerApiCalls.groupAssets as gax.GaxCall,
       request,
@@ -2364,6 +2412,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       parent: request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.groupFindings(request, options, callback);
   }
 
@@ -2508,6 +2557,7 @@ export class SecurityCenterClient {
       parent: request.parent || '',
     });
     const callSettings = new gax.CallSettings(options);
+    this.initialize();
     return this._descriptors.page.groupFindings.createStream(
       this._innerApiCalls.groupFindings as gax.GaxCall,
       request,
@@ -2721,6 +2771,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       parent: request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.listAssets(request, options, callback);
   }
 
@@ -2886,6 +2937,7 @@ export class SecurityCenterClient {
       parent: request.parent || '',
     });
     const callSettings = new gax.CallSettings(options);
+    this.initialize();
     return this._descriptors.page.listAssets.createStream(
       this._innerApiCalls.listAssets as gax.GaxCall,
       request,
@@ -3087,6 +3139,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       parent: request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.listFindings(request, options, callback);
   }
 
@@ -3237,6 +3290,7 @@ export class SecurityCenterClient {
       parent: request.parent || '',
     });
     const callSettings = new gax.CallSettings(options);
+    this.initialize();
     return this._descriptors.page.listFindings.createStream(
       this._innerApiCalls.listFindings as gax.GaxCall,
       request,
@@ -3332,6 +3386,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       parent: request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.listNotificationConfigs(
       request,
       options,
@@ -3383,6 +3438,7 @@ export class SecurityCenterClient {
       parent: request.parent || '',
     });
     const callSettings = new gax.CallSettings(options);
+    this.initialize();
     return this._descriptors.page.listNotificationConfigs.createStream(
       this._innerApiCalls.listNotificationConfigs as gax.GaxCall,
       request,
@@ -3478,6 +3534,7 @@ export class SecurityCenterClient {
     ] = gax.routingHeader.fromParams({
       parent: request.parent || '',
     });
+    this.initialize();
     return this._innerApiCalls.listSources(request, options, callback);
   }
 
@@ -3525,6 +3582,7 @@ export class SecurityCenterClient {
       parent: request.parent || '',
     });
     const callSettings = new gax.CallSettings(options);
+    this.initialize();
     return this._descriptors.page.listSources.createStream(
       this._innerApiCalls.listSources as gax.GaxCall,
       request,
@@ -3862,8 +3920,9 @@ export class SecurityCenterClient {
    * The client will no longer be usable and all future behavior is undefined.
    */
   close(): Promise<void> {
+    this.initialize();
     if (!this._terminated) {
-      return this.securityCenterStub.then(stub => {
+      return this.securityCenterStub!.then(stub => {
         this._terminated = true;
         stub.close();
       });
diff --git a/packages/google-cloud-securitycenter/synth.metadata b/packages/google-cloud-securitycenter/synth.metadata
index 414e2b09298..0925f1e5dbb 100644
--- a/packages/google-cloud-securitycenter/synth.metadata
+++ b/packages/google-cloud-securitycenter/synth.metadata
@@ -1,13 +1,13 @@
 {
-  "updateTime": "2020-03-04T12:40:40.245405Z",
+  "updateTime": "2020-03-05T23:15:57.060814Z",
   "sources": [
     {
       "git": {
         "name": "googleapis",
         "remote": "https://github.com/googleapis/googleapis.git",
-        "sha": "541b1ded4abadcc38e8178680b0677f65594ea6f",
-        "internalRef": "298686266",
-        "log": "541b1ded4abadcc38e8178680b0677f65594ea6f\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"
+        "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\n"
       }
     },
     {
diff --git a/packages/google-cloud-securitycenter/test/gapic-security_center-v1.ts b/packages/google-cloud-securitycenter/test/gapic-security_center-v1.ts
index 79521a6a46e..fb12e4f462f 100644
--- a/packages/google-cloud-securitycenter/test/gapic-security_center-v1.ts
+++ b/packages/google-cloud-securitycenter/test/gapic-security_center-v1.ts
@@ -104,12 +104,30 @@ describe('v1.SecurityCenterClient', () => {
     });
     assert(client);
   });
+  it('has initialize method and supports deferred initialization', async () => {
+    const client = new securitycenterModule.v1.SecurityCenterClient({
+      credentials: {client_email: 'bogus', private_key: 'bogus'},
+      projectId: 'bogus',
+    });
+    assert.strictEqual(client.securityCenterStub, undefined);
+    await client.initialize();
+    assert(client.securityCenterStub);
+  });
+  it('has close method', () => {
+    const client = new securitycenterModule.v1.SecurityCenterClient({
+      credentials: {client_email: 'bogus', private_key: 'bogus'},
+      projectId: 'bogus',
+    });
+    client.close();
+  });
   describe('createSource', () => {
     it('invokes createSource without error', done => {
       const client = new securitycenterModule.v1.SecurityCenterClient({
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.ICreateSourceRequest = {};
       request.parent = '';
@@ -133,6 +151,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.ICreateSourceRequest = {};
       request.parent = '';
@@ -158,6 +178,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.ICreateFindingRequest = {};
       request.parent = '';
@@ -181,6 +203,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.ICreateFindingRequest = {};
       request.parent = '';
@@ -206,6 +230,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.ICreateNotificationConfigRequest = {};
       request.parent = '';
@@ -229,6 +255,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.ICreateNotificationConfigRequest = {};
       request.parent = '';
@@ -257,6 +285,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.IDeleteNotificationConfigRequest = {};
       request.name = '';
@@ -280,6 +310,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.IDeleteNotificationConfigRequest = {};
       request.name = '';
@@ -308,6 +340,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.iam.v1.IGetIamPolicyRequest = {};
       request.resource = '';
@@ -331,6 +365,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.iam.v1.IGetIamPolicyRequest = {};
       request.resource = '';
@@ -356,6 +392,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.IGetNotificationConfigRequest = {};
       request.name = '';
@@ -379,6 +417,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.IGetNotificationConfigRequest = {};
       request.name = '';
@@ -404,6 +444,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.IGetOrganizationSettingsRequest = {};
       request.name = '';
@@ -427,6 +469,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.IGetOrganizationSettingsRequest = {};
       request.name = '';
@@ -455,6 +499,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.IGetSourceRequest = {};
       request.name = '';
@@ -478,6 +524,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.IGetSourceRequest = {};
       request.name = '';
@@ -503,6 +551,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.ISetFindingStateRequest = {};
       request.name = '';
@@ -526,6 +576,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.ISetFindingStateRequest = {};
       request.name = '';
@@ -551,6 +603,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.iam.v1.ISetIamPolicyRequest = {};
       request.resource = '';
@@ -574,6 +628,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.iam.v1.ISetIamPolicyRequest = {};
       request.resource = '';
@@ -599,6 +655,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.iam.v1.ITestIamPermissionsRequest = {};
       request.resource = '';
@@ -622,6 +680,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.iam.v1.ITestIamPermissionsRequest = {};
       request.resource = '';
@@ -647,6 +707,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.IUpdateFindingRequest = {};
       request.finding = {};
@@ -671,6 +733,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.IUpdateFindingRequest = {};
       request.finding = {};
@@ -697,6 +761,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.IUpdateNotificationConfigRequest = {};
       request.notificationConfig = {};
@@ -721,6 +787,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.IUpdateNotificationConfigRequest = {};
       request.notificationConfig = {};
@@ -750,6 +818,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.IUpdateOrganizationSettingsRequest = {};
       request.organizationSettings = {};
@@ -774,6 +844,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.IUpdateOrganizationSettingsRequest = {};
       request.organizationSettings = {};
@@ -803,6 +875,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.IUpdateSourceRequest = {};
       request.source = {};
@@ -827,6 +901,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.IUpdateSourceRequest = {};
       request.source = {};
@@ -853,6 +929,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.IUpdateSecurityMarksRequest = {};
       request.securityMarks = {};
@@ -877,6 +955,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.IUpdateSecurityMarksRequest = {};
       request.securityMarks = {};
@@ -903,6 +983,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.IRunAssetDiscoveryRequest = {};
       request.parent = '';
@@ -933,6 +1015,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.IRunAssetDiscoveryRequest = {};
       request.parent = '';
@@ -966,6 +1050,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.IGroupAssetsRequest = {};
       request.parent = '';
@@ -993,6 +1079,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.IGroupAssetsRequest = {};
       request.parent = '';
@@ -1025,6 +1113,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.IGroupFindingsRequest = {};
       request.parent = '';
@@ -1052,6 +1142,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.IGroupFindingsRequest = {};
       request.parent = '';
@@ -1084,6 +1176,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.IListAssetsRequest = {};
       request.parent = '';
@@ -1111,6 +1205,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.IListAssetsRequest = {};
       request.parent = '';
@@ -1143,6 +1239,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.IListFindingsRequest = {};
       request.parent = '';
@@ -1170,6 +1268,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.IListFindingsRequest = {};
       request.parent = '';
@@ -1202,6 +1302,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.IListNotificationConfigsRequest = {};
       request.parent = '';
@@ -1232,6 +1334,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.IListNotificationConfigsRequest = {};
       request.parent = '';
@@ -1264,6 +1368,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.IListSourcesRequest = {};
       request.parent = '';
@@ -1291,6 +1397,8 @@ describe('v1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1.IListSourcesRequest = {};
       request.parent = '';
diff --git a/packages/google-cloud-securitycenter/test/gapic-security_center-v1beta1.ts b/packages/google-cloud-securitycenter/test/gapic-security_center-v1beta1.ts
index 1425d84de26..098ce8a0cbe 100644
--- a/packages/google-cloud-securitycenter/test/gapic-security_center-v1beta1.ts
+++ b/packages/google-cloud-securitycenter/test/gapic-security_center-v1beta1.ts
@@ -104,12 +104,30 @@ describe('v1beta1.SecurityCenterClient', () => {
     });
     assert(client);
   });
+  it('has initialize method and supports deferred initialization', async () => {
+    const client = new securitycenterModule.v1beta1.SecurityCenterClient({
+      credentials: {client_email: 'bogus', private_key: 'bogus'},
+      projectId: 'bogus',
+    });
+    assert.strictEqual(client.securityCenterStub, undefined);
+    await client.initialize();
+    assert(client.securityCenterStub);
+  });
+  it('has close method', () => {
+    const client = new securitycenterModule.v1beta1.SecurityCenterClient({
+      credentials: {client_email: 'bogus', private_key: 'bogus'},
+      projectId: 'bogus',
+    });
+    client.close();
+  });
   describe('createSource', () => {
     it('invokes createSource without error', done => {
       const client = new securitycenterModule.v1beta1.SecurityCenterClient({
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1beta1.ICreateSourceRequest = {};
       request.parent = '';
@@ -133,6 +151,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1beta1.ICreateSourceRequest = {};
       request.parent = '';
@@ -158,6 +178,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1beta1.ICreateFindingRequest = {};
       request.parent = '';
@@ -181,6 +203,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1beta1.ICreateFindingRequest = {};
       request.parent = '';
@@ -206,6 +230,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.iam.v1.IGetIamPolicyRequest = {};
       request.resource = '';
@@ -229,6 +255,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.iam.v1.IGetIamPolicyRequest = {};
       request.resource = '';
@@ -254,6 +282,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1beta1.IGetOrganizationSettingsRequest = {};
       request.name = '';
@@ -277,6 +307,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1beta1.IGetOrganizationSettingsRequest = {};
       request.name = '';
@@ -305,6 +337,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1beta1.IGetSourceRequest = {};
       request.name = '';
@@ -328,6 +362,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1beta1.IGetSourceRequest = {};
       request.name = '';
@@ -353,6 +389,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1beta1.ISetFindingStateRequest = {};
       request.name = '';
@@ -376,6 +414,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1beta1.ISetFindingStateRequest = {};
       request.name = '';
@@ -401,6 +441,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.iam.v1.ISetIamPolicyRequest = {};
       request.resource = '';
@@ -424,6 +466,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.iam.v1.ISetIamPolicyRequest = {};
       request.resource = '';
@@ -449,6 +493,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.iam.v1.ITestIamPermissionsRequest = {};
       request.resource = '';
@@ -472,6 +518,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.iam.v1.ITestIamPermissionsRequest = {};
       request.resource = '';
@@ -497,6 +545,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1beta1.IUpdateFindingRequest = {};
       request.finding = {};
@@ -521,6 +571,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1beta1.IUpdateFindingRequest = {};
       request.finding = {};
@@ -547,6 +599,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1beta1.IUpdateOrganizationSettingsRequest = {};
       request.organizationSettings = {};
@@ -571,6 +625,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1beta1.IUpdateOrganizationSettingsRequest = {};
       request.organizationSettings = {};
@@ -600,6 +656,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1beta1.IUpdateSourceRequest = {};
       request.source = {};
@@ -624,6 +682,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1beta1.IUpdateSourceRequest = {};
       request.source = {};
@@ -650,6 +710,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1beta1.IUpdateSecurityMarksRequest = {};
       request.securityMarks = {};
@@ -674,6 +736,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1beta1.IUpdateSecurityMarksRequest = {};
       request.securityMarks = {};
@@ -700,6 +764,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1beta1.IRunAssetDiscoveryRequest = {};
       request.parent = '';
@@ -730,6 +796,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1beta1.IRunAssetDiscoveryRequest = {};
       request.parent = '';
@@ -763,6 +831,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1beta1.IGroupAssetsRequest = {};
       request.parent = '';
@@ -790,6 +860,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1beta1.IGroupAssetsRequest = {};
       request.parent = '';
@@ -822,6 +894,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1beta1.IGroupFindingsRequest = {};
       request.parent = '';
@@ -849,6 +923,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1beta1.IGroupFindingsRequest = {};
       request.parent = '';
@@ -881,6 +957,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1beta1.IListAssetsRequest = {};
       request.parent = '';
@@ -908,6 +986,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1beta1.IListAssetsRequest = {};
       request.parent = '';
@@ -940,6 +1020,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1beta1.IListFindingsRequest = {};
       request.parent = '';
@@ -967,6 +1049,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1beta1.IListFindingsRequest = {};
       request.parent = '';
@@ -999,6 +1083,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1beta1.IListSourcesRequest = {};
       request.parent = '';
@@ -1026,6 +1112,8 @@ describe('v1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1beta1.IListSourcesRequest = {};
       request.parent = '';
diff --git a/packages/google-cloud-securitycenter/test/gapic-security_center-v1p1beta1.ts b/packages/google-cloud-securitycenter/test/gapic-security_center-v1p1beta1.ts
index 07995433eb0..c60edab460a 100644
--- a/packages/google-cloud-securitycenter/test/gapic-security_center-v1p1beta1.ts
+++ b/packages/google-cloud-securitycenter/test/gapic-security_center-v1p1beta1.ts
@@ -104,12 +104,30 @@ describe('v1p1beta1.SecurityCenterClient', () => {
     });
     assert(client);
   });
+  it('has initialize method and supports deferred initialization', async () => {
+    const client = new securitycenterModule.v1p1beta1.SecurityCenterClient({
+      credentials: {client_email: 'bogus', private_key: 'bogus'},
+      projectId: 'bogus',
+    });
+    assert.strictEqual(client.securityCenterStub, undefined);
+    await client.initialize();
+    assert(client.securityCenterStub);
+  });
+  it('has close method', () => {
+    const client = new securitycenterModule.v1p1beta1.SecurityCenterClient({
+      credentials: {client_email: 'bogus', private_key: 'bogus'},
+      projectId: 'bogus',
+    });
+    client.close();
+  });
   describe('createSource', () => {
     it('invokes createSource without error', done => {
       const client = new securitycenterModule.v1p1beta1.SecurityCenterClient({
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.ICreateSourceRequest = {};
       request.parent = '';
@@ -133,6 +151,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.ICreateSourceRequest = {};
       request.parent = '';
@@ -158,6 +178,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.ICreateFindingRequest = {};
       request.parent = '';
@@ -181,6 +203,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.ICreateFindingRequest = {};
       request.parent = '';
@@ -206,6 +230,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.ICreateNotificationConfigRequest = {};
       request.parent = '';
@@ -229,6 +255,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.ICreateNotificationConfigRequest = {};
       request.parent = '';
@@ -257,6 +285,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.IDeleteNotificationConfigRequest = {};
       request.name = '';
@@ -280,6 +310,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.IDeleteNotificationConfigRequest = {};
       request.name = '';
@@ -308,6 +340,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.iam.v1.IGetIamPolicyRequest = {};
       request.resource = '';
@@ -331,6 +365,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.iam.v1.IGetIamPolicyRequest = {};
       request.resource = '';
@@ -356,6 +392,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.IGetNotificationConfigRequest = {};
       request.name = '';
@@ -379,6 +417,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.IGetNotificationConfigRequest = {};
       request.name = '';
@@ -404,6 +444,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.IGetOrganizationSettingsRequest = {};
       request.name = '';
@@ -427,6 +469,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.IGetOrganizationSettingsRequest = {};
       request.name = '';
@@ -455,6 +499,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.IGetSourceRequest = {};
       request.name = '';
@@ -478,6 +524,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.IGetSourceRequest = {};
       request.name = '';
@@ -503,6 +551,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.ISetFindingStateRequest = {};
       request.name = '';
@@ -526,6 +576,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.ISetFindingStateRequest = {};
       request.name = '';
@@ -551,6 +603,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.iam.v1.ISetIamPolicyRequest = {};
       request.resource = '';
@@ -574,6 +628,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.iam.v1.ISetIamPolicyRequest = {};
       request.resource = '';
@@ -599,6 +655,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.iam.v1.ITestIamPermissionsRequest = {};
       request.resource = '';
@@ -622,6 +680,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.iam.v1.ITestIamPermissionsRequest = {};
       request.resource = '';
@@ -647,6 +707,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.IUpdateFindingRequest = {};
       request.finding = {};
@@ -671,6 +733,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.IUpdateFindingRequest = {};
       request.finding = {};
@@ -697,6 +761,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.IUpdateNotificationConfigRequest = {};
       request.notificationConfig = {};
@@ -721,6 +787,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.IUpdateNotificationConfigRequest = {};
       request.notificationConfig = {};
@@ -750,6 +818,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.IUpdateOrganizationSettingsRequest = {};
       request.organizationSettings = {};
@@ -774,6 +844,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.IUpdateOrganizationSettingsRequest = {};
       request.organizationSettings = {};
@@ -803,6 +875,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.IUpdateSourceRequest = {};
       request.source = {};
@@ -827,6 +901,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.IUpdateSourceRequest = {};
       request.source = {};
@@ -853,6 +929,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.IUpdateSecurityMarksRequest = {};
       request.securityMarks = {};
@@ -877,6 +955,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.IUpdateSecurityMarksRequest = {};
       request.securityMarks = {};
@@ -903,6 +983,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.IRunAssetDiscoveryRequest = {};
       request.parent = '';
@@ -933,6 +1015,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.IRunAssetDiscoveryRequest = {};
       request.parent = '';
@@ -966,6 +1050,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.IGroupAssetsRequest = {};
       request.parent = '';
@@ -993,6 +1079,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.IGroupAssetsRequest = {};
       request.parent = '';
@@ -1025,6 +1113,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.IGroupFindingsRequest = {};
       request.parent = '';
@@ -1052,6 +1142,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.IGroupFindingsRequest = {};
       request.parent = '';
@@ -1084,6 +1176,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.IListAssetsRequest = {};
       request.parent = '';
@@ -1111,6 +1205,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.IListAssetsRequest = {};
       request.parent = '';
@@ -1143,6 +1239,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.IListFindingsRequest = {};
       request.parent = '';
@@ -1170,6 +1268,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.IListFindingsRequest = {};
       request.parent = '';
@@ -1202,6 +1302,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.IListNotificationConfigsRequest = {};
       request.parent = '';
@@ -1232,6 +1334,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.IListNotificationConfigsRequest = {};
       request.parent = '';
@@ -1264,6 +1368,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.IListSourcesRequest = {};
       request.parent = '';
@@ -1291,6 +1397,8 @@ describe('v1p1beta1.SecurityCenterClient', () => {
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
+      // Initialize client before mocking
+      client.initialize();
       // Mock request
       const request: protosTypes.google.cloud.securitycenter.v1p1beta1.IListSourcesRequest = {};
       request.parent = '';