When testing telemetry, pub/sub, or any broadcast mechanism with
async: true, events from concurrent tests can leak into mailbox.
Fix: Pin-match on unique identifier to filter.
Two-part pattern:
1. Filter at source — only forward events matching test's identifier
2. Pin in assertion — ^variable rejects mismatches that slip through
Applies to telemetry handlers, PubSub, GenStage/Broadway consumers,
any shared message bus.
Triggered by PR #710 flaky test fix in gargoyle.
Rodin
df9c856d96