otherwise we try to reschedule the socket we've just closed.

libevent is a very cool library, I like the APIs and enjoy using it. However, telescope is not as large and doesn't have as many file descriptor, so libevent is quite ``too big'' for our needs. ev started as a small event loop on top of poll(2) for amused, and can be used here too, it just needed to grow the ability to handle several timers, as we need quite some on telescope (in fact, we use more timers than fds!)

unfortunate, but a small coupling with either poll(2) or ev is needed.

We can't add items to the heap while we've iterating it, so we can't directly insert new times from a timer' callback. Instead, add them to a ``reserve'' space after the end of the heap, and merge them back inside the heap after all events have been processed.