GlobalRateLimiter.acquire() enforced the inter-message gap inside an
async-with that released the lock before returning, so the caller's
radio transmission ran with no lock held and every room's sync loop
could push concurrently. acquire() now returns with the lock held
(released via release() in a finally, including on cancellation during
the gap wait), uses a monotonic clock so wall-clock jumps cannot skip
or stretch the gap, and push_post_to_client acquires it only around the
sync-state write plus the blocking send, so the ACK-timeout clock
starts when the transmission actually begins. Regression tests cover
two rooms sharing one limiter (no concurrent sends, gap enforced) and
lock release when the send raises.
agessaman
ef234f143b