private com.google.protobuf.SingleFieldBuilderV3<
            com.google.cloud.texttospeech.v1.AdvancedVoiceOptions,
            com.google.cloud.texttospeech.v1.AdvancedVoiceOptions.Builder,
            com.google.cloud.texttospeech.v1.AdvancedVoiceOptionsOrBuilder>
        getAdvancedVoiceOptionsFieldBuilder() {
      if (advancedVoiceOptionsBuilder_ == null) {
        advancedVoiceOptionsBuilder_ =
            new com.google.protobuf.SingleFieldBuilderV3<
                com.google.cloud.texttospeech.v1.AdvancedVoiceOptions,
                com.google.cloud.texttospeech.v1.AdvancedVoiceOptions.Builder,
                com.google.cloud.texttospeech.v1.AdvancedVoiceOptionsOrBuilder>(
                getAdvancedVoiceOptions(), getParentForChildren(), isClean());
        advancedVoiceOptions_ = null;
      }
      return advancedVoiceOptionsBuilder_;
    }
<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