@java.lang.Override
  public com.google.protobuf.ByteString getRequestIdBytes() {
    java.lang.Object ref = requestId_;
    if (ref instanceof java.lang.String) {
      com.google.protobuf.ByteString b =
          com.google.protobuf.ByteString.copyFromUtf8((java.lang.String) ref);
      requestId_ = b;
      return b;
    } else {
      return (com.google.protobuf.ByteString) ref;
    }
  }
<pre>
Optional. The request ID must be a valid UUID with the exception that zero
UUID is not supported (00000000-0000-0000-0000-000000000000).
</pre>

<code>string request_id = 2 [(.google.api.field_behavior) = OPTIONAL];</code>

@return The bytes for requestId.
java-vmwareengine/proto-google-cloud-vmwareengine-v1/src/main/java/com/google/cloud/vmwareengine/v1/DeleteClusterRequest.java