public com.google.cloud.texttospeech.v1beta1.AudioConfigOrBuilder getAudioConfigOrBuilder() {
      if (audioConfigBuilder_ != null) {
        return audioConfigBuilder_.getMessageOrBuilder();
      } else {
        return audioConfig_ == null
            ? com.google.cloud.texttospeech.v1beta1.AudioConfig.getDefaultInstance()
            : audioConfig_;
      }
    }
<pre>
Required. The configuration of the synthesized audio.
</pre>

<code>
.google.cloud.texttospeech.v1beta1.AudioConfig audio_config = 3 [(.google.api.field_behavior) = REQUIRED];
</code>
java-texttospeech/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/SynthesizeLongAudioRequest.java