@java.lang.Override
  public int getSerializedSize() {
    int size = memoizedSize;
    if (size != -1) return size;

    size = 0;
    if (audioEncoding_
        != com.google.cloud.texttospeech.v1beta1.AudioEncoding.AUDIO_ENCODING_UNSPECIFIED
            .getNumber()) {
      size += com.google.protobuf.CodedOutputStream.computeEnumSize(1, audioEncoding_);
    }
    if (sampleRateHertz_ != 0) {
      size += com.google.protobuf.CodedOutputStream.computeInt32Size(2, sampleRateHertz_);
    }
    size += getUnknownFields().getSerializedSize();
    memoizedSize = size;
    return size;
  }
<pre>
Optional. The synthesis sample rate (in hertz) for this audio.
</pre>

<code>int32 sample_rate_hertz = 2 [(.google.api.field_behavior) = OPTIONAL];</code>

@return The sampleRateHertz.
java-texttospeech/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/StreamingAudioConfig.java