@java.lang.Override
    public Builder newBuilderForType() {
      return newBuilder();
    }
<pre>
The same object may be identified on muitiple frames which are typical
adjacent. The set of frames where a particular object has been detected
form a track. This track_id can be used to trace down all frames for an
detected object.
</pre>

<code>int64 track_id = 5;</code>

@return The trackId.
java-visionai/proto-google-cloud-visionai-v1/src/main/java/com/google/cloud/visionai/v1/VideoObjectTrackingPredictionResult.java