public Builder setStartTime(com.google.protobuf.Duration value) {
      if (startTimeBuilder_ == null) {
        if (value == null) {
          throw new NullPointerException();
        }
        startTime_ = value;
      } else {
        startTimeBuilder_.setMessage(value);
      }
      bitField0_ |= 0x00000001;
      onChanged();
      return this;
    }
<pre>
Output only. Time offset relative to the beginning of the audio, and
corresponding to the start of the spoken word. This field is only set if
`enable_word_time_offsets=true` and only in the top hypothesis. This is an
experimental feature and the accuracy of the time offset can vary.
</pre>

<code>.google.protobuf.Duration start_time = 1;</code>
java-video-intelligence/proto-google-cloud-video-intelligence-v1p1beta1/src/main/java/com/google/cloud/videointelligence/v1p1beta1/WordInfo.java