private com.google.protobuf.SingleFieldBuilderV3<
            com.google.cloud.videointelligence.v1p3beta1.Track,
            com.google.cloud.videointelligence.v1p3beta1.Track.Builder,
            com.google.cloud.videointelligence.v1p3beta1.TrackOrBuilder>
        getFaceTrackFieldBuilder() {
      if (faceTrackBuilder_ == null) {
        faceTrackBuilder_ =
            new com.google.protobuf.SingleFieldBuilderV3<
                com.google.cloud.videointelligence.v1p3beta1.Track,
                com.google.cloud.videointelligence.v1p3beta1.Track.Builder,
                com.google.cloud.videointelligence.v1p3beta1.TrackOrBuilder>(
                getFaceTrack(), getParentForChildren(), isClean());
        faceTrack_ = null;
      }
      return faceTrackBuilder_;
    }
<pre>
A track of a person's face.
</pre>

<code>.google.cloud.videointelligence.v1p3beta1.Track face_track = 3;</code>
java-video-intelligence/proto-google-cloud-video-intelligence-v1p3beta1/src/main/java/com/google/cloud/videointelligence/v1p3beta1/CelebrityTrack.java