public Builder setTotalBilledDuration(com.google.protobuf.Duration value) {
      if (totalBilledDurationBuilder_ == null) {
        if (value == null) {
          throw new NullPointerException();
        }
        totalBilledDuration_ = value;
      } else {
        totalBilledDurationBuilder_.setMessage(value);
      }
      bitField0_ |= 0x00000002;
      onChanged();
      return this;
    }
<pre>
When available, billed audio seconds for the corresponding request.
</pre>

<code>.google.protobuf.Duration total_billed_duration = 2;</code>
java-speech/proto-google-cloud-speech-v2/src/main/java/com/google/cloud/speech/v2/BatchRecognizeResponse.java