More on my earlier callout(9) question, I notice that
midi(4) has no reference to callout_stop() anywhere.
And yet it is a device that can detach and disappear
at any time (when you pull a USB cable, ferinstance).
Can that be right? Again, I've never seen a crash - is
there some way the callouts get canceled automagically,
or is it just luck?

-Chap