feat: add max_commit_delay API

PiperOrigin-RevId: 599315735

google/spanner/v1/spanner.proto

@@ -22,6 +22,7 @@ import "google/api/annotations.proto";
 import "google/api/client.proto";
 import "google/api/field_behavior.proto";
 import "google/api/resource.proto";
+import "google/protobuf/duration.proto";
 import "google/protobuf/empty.proto";
 import "google/protobuf/struct.proto";
 import "google/protobuf/timestamp.proto";
@@ -1163,6 +1164,14 @@ message CommitRequest {
   // Default value is `false`.
   bool return_commit_stats = 5;
 
+  // Optional. The amount of latency this request is willing to incur in order
+  // to improve throughput. If this field is not set, Spanner assumes requests
+  // are relatively latency sensitive and automatically determines an
+  // appropriate delay time. You can specify a batching delay value between 0
+  // and 500 ms.
+  google.protobuf.Duration max_commit_delay = 8
+      [(google.api.field_behavior) = OPTIONAL];
+
   // Common options for this request.
   RequestOptions request_options = 6;
 }