Wait for something interesting to happen, and issue events.
That is, basically, do one iteration of a main select loop, processing
- all of the events, and then return. This isn't needed for
- `TripeCommandDispatcher', but `runservices' wants it.
+ all of the events, and then return. This is used in the method
+ `TripeCommandDispatcher.mainloop', but that's mostly for the benefit of
+ `runservices'; if your I/O watcher has a different main loop, you can
+ drive it yourself.
"""
M.select()