private com.google.protobuf.SingleFieldBuilderV3<
            com.google.protobuf.Duration,
            com.google.protobuf.Duration.Builder,
            com.google.protobuf.DurationOrBuilder>
        getTotalBilledTimeFieldBuilder() {
      if (totalBilledTimeBuilder_ == null) {
        totalBilledTimeBuilder_ =
            new com.google.protobuf.SingleFieldBuilderV3<
                com.google.protobuf.Duration,
                com.google.protobuf.Duration.Builder,
                com.google.protobuf.DurationOrBuilder>(
                getTotalBilledTime(), getParentForChildren(), isClean());
        totalBilledTime_ = null;
      }
      return totalBilledTimeBuilder_;
    }
<pre>
When available, billed audio seconds for the stream.
Set only if this is the last response in the stream.
</pre>

<code>.google.protobuf.Duration total_billed_time = 5;</code>
java-speech/proto-google-cloud-speech-v1/src/main/java/com/google/cloud/speech/v1/StreamingRecognizeResponse.java