public void markComplete() {
      // Notify to clear pending events, if any.
      lock.lock();
      try {
        condition.signal();
      } finally {
        lock.unlock();
      }
    }
Increasing the heartbeat interval can delay the delivery of events. Sending just updated
records would save CPU in DAG AM, but certain counters are updated very frequently. Until
real time decisions are made based on these counters, it can be sent once per second.
llap-server/src/java/org/apache/hadoop/hive/llap/daemon/impl/LlapTaskReporter.java