feat: add exactly once delivery flag

PiperOrigin-RevId: 426415626

google/pubsub/v1/pubsub.proto

@@ -1176,15 +1176,50 @@ message StreamingPullRequest {
 // Response for the `StreamingPull` method. This response is used to stream
 // messages from the server to the client.
 message StreamingPullResponse {
+  // Acknowledgement IDs sent in one or more previous requests to acknowledge a
+  // previously received message.
+  message AcknowledgeConfirmation {
+    // Successfully processed acknowledgement IDs.
+    repeated string ack_ids = 1 [ctype = CORD];
+
+    // List of acknowledgement IDs that were malformed or whose acknowledgement
+    // deadline has expired.
+    repeated string invalid_ack_ids = 2 [ctype = CORD];
+
+    // List of acknowledgement IDs that were out of order.
+    repeated string unordered_ack_ids = 3 [ctype = CORD];
+  }
+
+  // Acknowledgement IDs sent in one or more previous requests to modify the
+  // deadline for a specific message.
+  message ModifyAckDeadlineConfirmation {
+    // Successfully processed acknowledgement IDs.
+    repeated string ack_ids = 1 [ctype = CORD];
+
+    // List of acknowledgement IDs that were malformed or whose acknowledgement
+    // deadline has expired.
+    repeated string invalid_ack_ids = 2 [ctype = CORD];
+  }
+
   // Subscription properties sent as part of the response.
   message SubscriptionProperties {
+    // True iff exactly once delivery is enabled for this subscription.
+    bool exactly_once_delivery_enabled = 1;
     // True iff message ordering is enabled for this subscription.
     bool message_ordering_enabled = 2;
   }
 
   // Received Pub/Sub messages. This will not be empty.
   repeated ReceivedMessage received_messages = 1;
 
+  // This field will only be set if `enable_exactly_once_delivery` is set to
+  // `true`.
+  AcknowledgeConfirmation acknowlege_confirmation = 2;
+
+  // This field will only be set if `enable_exactly_once_delivery` is set to
+  // `true`.
+  ModifyAckDeadlineConfirmation modify_ack_deadline_confirmation = 3;
+
   // Properties associated with this subscription.
   SubscriptionProperties subscription_properties = 4;
 }