docs: @SuppressWarnings("deprecation")
      private final void operationTimeout() {
  
          /**
           * first kill async http worker; before suicide LESSON: MUST KILL AND
           * WAIT FOR CHILDREN to reply back before kill itself.
           */
          cancelCancellable();
          if (asyncWorker != null && !asyncWorker.isTerminated()) {
              asyncWorker
                      .tell(RequestWorkerMsgType.PROCESS_ON_TIMEOUT, getSelf());
  
          } else {
              logger.info("asyncWorker has been killed or uninitialized (null). "
                      + "Not send PROCESS ON TIMEOUT.\nREQ: "
                      + request.toString());
              replyErrors(PcConstants.OPERATION_TIMEOUT,
                      PcConstants.OPERATION_TIMEOUT, PcConstants.NA,
                      PcConstants.NA_INT);
          }
  
      }