void updateTaskAttempt(TezTaskAttemptID attemptId, boolean isGuaranteed) {
      Boolean oldVal = tasks.replace(attemptId, isGuaranteed);
      if (oldVal == null) {
        LOG.warn("Task " + attemptId + " is no longer registered");
        tasks.remove(attemptId);
      }
    }
Responsible for communicating with various AMs.
llap-server/src/java/org/apache/hadoop/hive/llap/daemon/impl/AMReporter.java