@java.lang.Override
  public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io.IOException {
    if (((bitField0_ & 0x00000001) != 0)) {
      output.writeMessage(6, getTotalBilledDuration());
    }
    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(requestId_)) {
      com.google.protobuf.GeneratedMessageV3.writeString(output, 9, requestId_);
    }
    getUnknownFields().writeTo(output);
  }
<pre>
When available, billed audio seconds for the corresponding request.
</pre>

<code>.google.protobuf.Duration total_billed_duration = 6;</code>
java-speech/proto-google-cloud-speech-v2/src/main/java/com/google/cloud/speech/v2/RecognitionResponseMetadata.java