@java.lang.Override
  public boolean hasCustomVoice() {
    return ((bitField0_ & 0x00000001) != 0);
  }
<pre>
The configuration for a custom voice. If [CustomVoiceParams.model] is set,
the service will choose the custom voice matching the specified
configuration.
</pre>

<code>.google.cloud.texttospeech.v1beta1.CustomVoiceParams custom_voice = 4;</code>

@return Whether the customVoice field is set.
java-texttospeech/proto-google-cloud-texttospeech-v1beta1/src/main/java/com/google/cloud/texttospeech/v1beta1/VoiceSelectionParams.java