pub fn clear_draw_request()Expand description
Reset the per-frame draw flags. The App::paint entry point calls
this before delegating to the root widget so each frame starts fresh —
widgets that still need a draw (animation in flight, focus blink, etc.)
must re-arm during their draw, otherwise the loop goes idle.
Also syncs this thread’s cross-thread async-wakeup bookkeeping so a
stale bump from before this clear cannot reappear on the next
wants_draw read. Without that sync, parallel tests calling
signal_async_state_change would leak wakeups into unrelated
tests that rely on wants_draw() returning false after a clear.