[glen-84]

Summary

• DisposeAsync_Should_DisposeBrokerConnection_When_BrokerIsDisposed started a fire-and-forget MoveNextAsync() and then disposed the subscription enumerator while it was still pending. Disposing an IAsyncEnumerator mid-MoveNextAsync is illegal, so the compiler-generated async iterator threw NotSupportedException ("Specified method is not supported.") under CI threadpool contention.
• The test now awaits the in-flight subscription before the enumerator is disposed, and asserts that disposing the broker cancels its active subscription. The iterator is never disposed while a MoveNextAsync is running, and block 1 gains a real assertion (it previously had none).
• Test-only change; no product code is affected.

Test plan

• Reproduced the exact exception deterministically with a standalone async-iterator repro (unawaited MoveNextAsync + DisposeAsync).
• Ran the fixed test 30x under multicore CPU stress — all green.

[Copilot]

Pull request overview

Fixes a race in the Fusion NATS subscription dispose test by ensuring an in-flight MoveNextAsync() is awaited (and observed) before the async enumerator is disposed, preventing illegal mid-MoveNextAsync disposal behavior.

Changes:

• Capture the in-flight MoveNextAsync() task instead of fire-and-forget.
• Dispose the broker and assert that the active subscription is canceled, avoiding disposing an async iterator while it is running.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.