Standardize the code we have in place to avoid creating too many
timer objects. We do not need exact timers for things that don't
need to be run ASAP, so we can play things fast and loose to avoid
wasting power with unnecessary wakeups.
We only need two classes of timers:
* asap - run this on the next loop tick, after operating on
@Danga::Socket::ToClose to close remaining sockets
* later - run at some point in the future. It could be as
soon as immediately (like "asap"), and as late as 60s into
the future.
In the future, we support an "emergency" switch to fire "later"
timers immediately.