All event handlers which call disconnect() MUST be registered using
`add_event_handler(..., threaded=True)` in order to prevent temporarily
deadlocking until a timeout occurs.
This is required because disconnect() waits for the main threads to
exit before returning, including the event processing thread. Since
handlers registered without `threaded=True` run in the event processing
thread, the disconnect() call will deadlock.
Lance Stout
e918a86028