pub type NextDeadlineFn = unsafe extern "C" fn(*mut c_void) -> u64;Expand description
phase-436 B2 — the other half of the seam, for the boards that now use it.
port_park above is what a port hands the executor to WAIT with;
these are what it hands the executor to be told WHEN. A board registering
a deadline source receives a WakeSourceId and reads it back out of
Executor::last_park(), so without this re-export it could match on
neither.
When this source will next need the executor, in the executor’s clock,
as microseconds FROM NOW.
u64::MAX means “nothing pending” — the source does not shorten the park.
That is how an ASYNC source spells itself: a socket or a DDS listener
contributes no deadline and instead breaks the park by signalling the wake
primitive, so async and deadline sources compose without a second
mechanism.