code: @Override
    protected synchronized void purgeJob(KillJobAction action) throws IOException {
      JobID jobId = action.getJobID();
      JobTrackerReporter reporter = jobTrackerReporters.remove(jobId);
      if (reporter != null) {
        reporter.shutdown();
      }
      super.purgeJob(action);
      crReleaseManager.returnRelease(jobId);
    }
docs: Override this to shutdown the heartbeat the the corresponding jobtracker