[dborgards]

What does this change?

IsoTpChannel.Dispose detached its handler from the actor before disposing the actor it owns. That Dispose is where the actor reports a callback that outlived its shutdown bound — a TimeoutException through its BackgroundExceptionOccurred — so the channel's subscribers never heard of it. The handler now comes off after the owned actor's Dispose; for an injected actor nothing runs between the two, so it is detached as before. Same ordering as #437 for the J1939-TP channel (#421) and #414 for the node; #448 already did it for the constructor's catch.

An internal ownsActor constructor seam (as on J1939TpChannel since #437) hands an injected actor to the channel to dispose, so the test can give the channel's own actor a 50 ms shutdown bound. The test holds the actor's loop with a callback released only in finally, so the bound is always exceeded — nothing is asserted against the clock — and awaits the report on a signal, since #418 it is dispatched on the thread pool.

• Test: IsoTpChannelIntegrationTests.The_Shutdown_Timeout_Of_The_Channels_Own_Actor_Reaches_Its_Subscribers
• Mutation: unsubscribe before _actor.Dispose() (the old order) → the test fails (signal never set, TimeoutException from the wait); restored → green.

Closes #449

Type of change

• feat — new behaviour (minor release)
• fix / perf — bug or performance fix (patch release)
• docs / test / refactor / chore / ci — no release
• Breaking change (! in the title, plus a BREAKING CHANGE: footer explaining the migration)

Checklist

• Build with -p:CI=true, test (net10.0), dotnet format --verify-no-changes, and pack +
  eng/verify-packages.py all pass locally (CONTRIBUTING.md § "Before you push") — full net10.0 suite green
• Public API changes are documented with XML comments — no public API change (the seam is an internal constructor parameter, documented in its remarks)
• New behaviour is covered by a test
• The requirement or ADR this relates to is referenced (e.g. FR-RAW-031, ADR-7), if any

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Generated by Claude Code

[cursor]

PR Summary

Low Risk
Narrow dispose-ordering fix with integration test coverage; behavior change only when an owned actor hits shutdown timeout during channel disposal.

Overview
IsoTpChannel.Dispose no longer unsubscribes from the actor’s BackgroundExceptionOccurred before disposing an owned actor. Shutdown now runs _actor.Dispose() first so a TimeoutException from a callback that outlived the actor’s shutdown bound is still forwarded to the channel’s subscribers; the handler is detached afterward (same ordering as the J1939-TP fix in #437).

An internal ownsActor constructor flag lets tests inject an actor the channel will dispose (without creating its own), enabling The_Shutdown_Timeout_Of_The_Channels_Own_Actor_Reaches_Its_Subscribers: it holds the actor loop until after dispose and asserts the shutdown timeout surfaces as TimeoutException on BackgroundExceptionOccurred.

^{Reviewed by Cursor Bugbot for commit a7daeeb. Bugbot is set up for automated code reviews on this repo. Configure here.}

[chatgpt-codex-connector]

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Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-25T09:53:30.342750Z	a7daeeb	PR opened

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