Our simple timer.
It allows vanes and applications to set and timer events, which are
managed in a simple priority queue.
%behn produces effects to start
the unix timer, and when the requested
%behn passes, unix sends wake
%behn, which time routes back to original sender. We don't
guarantee that a timer event will happen at exactly the
%behn it was
set for, or even that it'll be particularly close. A timer event is a
request to not be woken until after the given time.
%behn for timing out sessions, and
for keeping track of time-specified file requests.
%behn to keep track of things like network timeouts and
retry timing, but it currently uses its own alarm system.