Danga::Socket defers close() syscalls until the end of the event
loop to avoid FD recycling. Unfortunately, this is dependent on
IO events firing and waking the process up from
poll/kevent/epoll_wait.
Without any I/O activity, a socket could remain in the
@Danga::Socket::ToClose array indefinitely. Thus, we will
trigger a fake IO event after running all timers to trigger
the deferred close in Danga::Socket::PostEventLoop.