Module waker 

Waking a blocked wait_events from another thread.

A program whose work arrives off the loop thread — a D-Bus reply, a socket, a timer thread, a finished download — needs the loop to notice it while the loop is asleep in wait_events. A ShellWaker is the handle that does it: cloned and sent to any thread, where wake makes the current wait return, or the next one return at once if none is running.

A wake carries nothing. It is a doorbell, not a message: the program puts its data in its own channel and then rings, and the loop, once wait_events has returned, drains that channel. That keeps every backend’s mechanism the same size — a byte on a pipe, a signalled event, one posted event — and no event type grows a variant for data the shell never looks at.

Wakes coalesce. Any number of wakes between two waits end at most the next one or two of them early; none is ever lost, and none piles up. A loop that wakes, drains its channel and waits again therefore never misses work sent while it was draining.

Structs

ShellWaker

Wakes one shell’s wait_events from any thread — see the module docs.