public Builder mergeTotalBilledTime(com.google.protobuf.Duration value) {
      if (totalBilledTimeBuilder_ == null) {
        if (((bitField0_ & 0x00000002) != 0)
            && totalBilledTime_ != null
            && totalBilledTime_ != com.google.protobuf.Duration.getDefaultInstance()) {
          getTotalBilledTimeBuilder().mergeFrom(value);
        } else {
          totalBilledTime_ = value;
        }
      } else {
        totalBilledTimeBuilder_.mergeFrom(value);
      }
      if (totalBilledTime_ != null) {
        bitField0_ |= 0x00000002;
        onChanged();
      }
      return this;
    }
<pre>
When available, billed audio seconds for the corresponding request.
</pre>

<code>.google.protobuf.Duration total_billed_time = 3;</code>
java-speech/proto-google-cloud-speech-v1/src/main/java/com/google/cloud/speech/v1/RecognizeResponse.java