public com.google.protobuf.ByteString getVttCaptionsBytes() {
      java.lang.Object ref = vttCaptions_;
      if (ref instanceof String) {
        com.google.protobuf.ByteString b =
            com.google.protobuf.ByteString.copyFromUtf8((java.lang.String) ref);
        vttCaptions_ = b;
        return b;
      } else {
        return (com.google.protobuf.ByteString) ref;
      }
    }
<pre>
The transcript for the audio file as VTT formatted captions. This is
populated only when `VTT` output is requested.
</pre>

<code>string vtt_captions = 2;</code>

@return The bytes for vttCaptions.
java-speech/proto-google-cloud-speech-v2/src/main/java/com/google/cloud/speech/v2/InlineResult.java