@Override
  public synchronized void unregisterTask(TezTaskAttemptID taskAttemptID) {
    LOG.info("Unregistered counters for fragment: {}", fragmentId);
    FragmentCountersMap.unregisterCountersForFragment(fragmentId);
    currentCallable.markComplete();
    currentCallable = null;
  }
This method should always be invoked before setting up heartbeats for another task running in
the same container.
llap-server/src/java/org/apache/hadoop/hive/llap/daemon/impl/LlapTaskReporter.java