An event-based M/M/1 queue. The arrival event models the arrival of customers, a new arrival is scheduled, a report is made and the arrival is appended to the queue. The service event takes arrival events, acquires the loket and schedules a departure event. The departure event releases the loket and terminates itself. Notice that an arrival event has a report, so it must be terminated, when the customer departs, otherwise no samples will be recorded in the histogram. Furthermore, the service event is made conditional and is never passivated, so it exists for the entire simulation and is invoked whenever a arrival or departure event fires. See entity for a process-oriented M/M/1 queue.