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

    size = 0;
    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(parent_)) {
      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(1, parent_);
    }
    if (((bitField0_ & 0x00000001) != 0)) {
      size += com.google.protobuf.CodedOutputStream.computeMessageSize(2, getInput());
    }
    if (((bitField0_ & 0x00000002) != 0)) {
      size += com.google.protobuf.CodedOutputStream.computeMessageSize(3, getAudioConfig());
    }
    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(outputGcsUri_)) {
      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(4, outputGcsUri_);
    }
    if (((bitField0_ & 0x00000004) != 0)) {
      size += com.google.protobuf.CodedOutputStream.computeMessageSize(5, getVoice());
    }
    size += getUnknownFields().getSerializedSize();
    memoizedSize = size;
    return size;
  }
<pre>
Required. The desired voice of the synthesized audio.
</pre>

<code>
.google.cloud.texttospeech.v1beta1.VoiceSelectionParams voice = 5 [(.google.api.field_behavior) = REQUIRED];
</code>
java-texttospeech/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/SynthesizeLongAudioRequest.java