@java.lang.Override
  public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io.IOException {
    if (((bitField0_ & 0x00000001) != 0)) {
      output.writeMessage(1, getUpdateMask());
    }
    if (((bitField0_ & 0x00000002) != 0)) {
      output.writeMessage(2, getCluster());
    }
    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(requestId_)) {
      com.google.protobuf.GeneratedMessageV3.writeString(output, 3, requestId_);
    }
    if (validateOnly_ != false) {
      output.writeBool(4, validateOnly_);
    }
    getUnknownFields().writeTo(output);
  }
<pre>
Optional. True if you want the request to be validated and not executed;
false otherwise.
</pre>

<code>bool validate_only = 4 [(.google.api.field_behavior) = OPTIONAL];</code>

@return The validateOnly.
java-vmwareengine/proto-google-cloud-vmwareengine-v1/src/main/java/com/google/cloud/vmwareengine/v1/UpdateClusterRequest.java