private com.google.protobuf.SingleFieldBuilderV3<
            com.google.cloud.visionai.v1.ReceiveEventsControlResponse,
            com.google.cloud.visionai.v1.ReceiveEventsControlResponse.Builder,
            com.google.cloud.visionai.v1.ReceiveEventsControlResponseOrBuilder>
        getControlFieldBuilder() {
      if (controlBuilder_ == null) {
        if (!(responseCase_ == 2)) {
          response_ =
              com.google.cloud.visionai.v1.ReceiveEventsControlResponse.getDefaultInstance();
        }
        controlBuilder_ =
            new com.google.protobuf.SingleFieldBuilderV3<
                com.google.cloud.visionai.v1.ReceiveEventsControlResponse,
                com.google.cloud.visionai.v1.ReceiveEventsControlResponse.Builder,
                com.google.cloud.visionai.v1.ReceiveEventsControlResponseOrBuilder>(
                (com.google.cloud.visionai.v1.ReceiveEventsControlResponse) response_,
                getParentForChildren(),
                isClean());
        response_ = null;
      }
      responseCase_ = 2;
      onChanged();
      return controlBuilder_;
    }
<pre>
A control message from the server.
</pre>

<code>.google.cloud.visionai.v1.ReceiveEventsControlResponse control = 2;</code>
java-visionai/proto-google-cloud-visionai-v1/src/main/java/com/google/cloud/visionai/v1/ReceiveEventsResponse.java