code: @SuppressWarnings("deprecation")
      private void cancelRequestAndWorkers() {
  
          for (ActorRef worker : workers.values()) {
              if (worker != null && !worker.isTerminated()) {
                  worker.tell(OperationWorkerMsgType.CANCEL, getSelf());
              }
          }
  
          logger.info("ExecutionManager sending cancelPendingRequest at time: "
                  + PcDateUtils.getNowDateTimeStr());
      }
docs: Cancel request and workers.