@java.lang.Override
  public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io.IOException {
    if (((bitField0_ & 0x00000001) != 0)) {
      output.writeMessage(1, getInput());
    }
    if (((bitField0_ & 0x00000002) != 0)) {
      output.writeMessage(2, getVoice());
    }
    if (((bitField0_ & 0x00000004) != 0)) {
      output.writeMessage(3, getAudioConfig());
    }
    if (((bitField0_ & 0x00000008) != 0)) {
      output.writeMessage(8, getAdvancedVoiceOptions());
    }
    getUnknownFields().writeTo(output);
  }
<pre>
Advanced voice options.
</pre>

<code>optional .google.cloud.texttospeech.v1.AdvancedVoiceOptions advanced_voice_options = 8;
</code>
java-texttospeech/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/SynthesizeSpeechRequest.java