code: private void cancelPendingSlotRequest(PendingSlotRequest pendingSlotRequest) {
  		CompletableFuture<Acknowledge> request = pendingSlotRequest.getRequestFuture();
  
  		returnPendingTaskManagerSlotIfAssigned(pendingSlotRequest);
  
  		if (null != request) {
  			request.cancel(false);
  		}
  	}
docs: Cancels the given slot request.
  
  @param pendingSlotRequest to cancel