fn wake(wake_win: &AtomicU32)Expand description
Wake the parked monitor: a ClientMessage to its private window (SendEvent with an empty
mask delivers to the window’s creator) from a short-lived connection. The send is
round-tripped (check) so a failure has a name, and the whole wake is retried once. A
zero window means setup hasn’t finished; the thread re-checks its flags before first
parking, so the wake can be skipped.