A fifth review found two gaps. A scheduled trial that returned False was re-armed at once, but False also follows exhausted no_event_received retries, so the radio could be tried again and again without another answered probe. And a reply's success settlement ran in a worker thread that a cancelled caller could cancel while it was still queued, stranding the trial in flight.
_end_offline_trial ends a trial that went out without succeeding (False or an exception, from a reply or a scheduled send) under the state lock alone; only paths where nothing reached the send still re-arm. The success settlement is shielded, so it completes even if the caller is cancelled. The cancellation test queues the settlement behind a busy one-worker executor and fails without the shield.
agessaman
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