public UnaryCallSettings.Builder<ListVoicesRequest, ListVoicesResponse> listVoicesSettings() {
      return listVoicesSettings;
    }
Returns the builder for the settings used for calls to listVoices.
java-texttospeech/google-cloud-texttospeech/src/main/java/com/google/cloud/texttospeech/v1beta1/stub/TextToSpeechStubSettings.java