@java.lang.Override
  public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io.IOException {
    for (int i = 0; i < languageCodes_.size(); i++) {
      com.google.protobuf.GeneratedMessageV3.writeString(output, 1, languageCodes_.getRaw(i));
    }
    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(name_)) {
      com.google.protobuf.GeneratedMessageV3.writeString(output, 2, name_);
    }
    if (ssmlGender_
        != com.google.cloud.texttospeech.v1.SsmlVoiceGender.SSML_VOICE_GENDER_UNSPECIFIED
            .getNumber()) {
      output.writeEnum(3, ssmlGender_);
    }
    if (naturalSampleRateHertz_ != 0) {
      output.writeInt32(4, naturalSampleRateHertz_);
    }
    getUnknownFields().writeTo(output);
  }
<pre>
The natural sample rate (in hertz) for this voice.
</pre>

<code>int32 natural_sample_rate_hertz = 4;</code>

@return The naturalSampleRateHertz.
java-texttospeech/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/Voice.java