@java.lang.Override
  public Builder toBuilder() {
    return this == DEFAULT_INSTANCE ? new Builder() : new Builder().mergeFrom(this);
  }
<pre>
The audio metadata of `audio_content`.
</pre>

<code>.google.cloud.texttospeech.v1beta1.AudioConfig audio_config = 4;</code>
java-texttospeech/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/SynthesizeSpeechResponse.java