code: boolean onHeartbeatStop()
    {
      SocketPool clusterSocketPool;
      
      if (isExternal()) {
        clusterSocketPool = _clusterSocketPool.getAndSet(null);
      }
      else {
        clusterSocketPool = _clusterSocketPool.get();
      }
  
      if (clusterSocketPool != null) {
        clusterSocketPool.getFactory().notifyHeartbeatStop();
      }
  
      /*
      if (! _heartbeatState.notifyHeartbeatStop()) {
        return false;
      }
      */
      
      log.fine("notify-heartbeat-stop " + this);
  
      return true;
    }
docs: Notify that a stop event has been received.