code: public void process() {
  
          /** Manages lists of coordinators, and callbacks which can come back async. */
          drainQueues();
  
          currentTime = timer.now();
  
          /* Check to see if callbacks completed or timed out. */
          monitorCallBacks();
  
          /* Check to see if coordinators completed or timed out. */
          monitorCallbackCoordinators();
  
          /* flush services. */
          collaboratingServices.forEach(ServiceProxyUtils::flushServiceProxy);
  
          processRepeatingTasks();
          processFireOnceTasks();
      }
docs: Process items in reactor.