public Builder clearVtt() {
      bitField0_ = (bitField0_ & ~0x00000002);
      vtt_ = null;
      if (vttBuilder_ != null) {
        vttBuilder_.dispose();
        vttBuilder_ = null;
      }
      onChanged();
      return this;
    }
<pre>
Configuration for the VTT output format. If this field is set, then
transcripts will be written to the sink in the VTT format.
</pre>

<code>.google.cloud.speech.v2.VttOutputFileFormatConfig vtt = 2;</code>
java-speech/proto-google-cloud-speech-v2/src/main/java/com/google/cloud/speech/v2/OutputFormatConfig.java