[Copilot]

Windows CI failed when the net462 cross-origin postMessage test timed out waiting for its asynchronous round-trip.

• Polling window: Extend the test helper’s wait from 4 to 10 seconds.
• Async continuation: Use ConfigureAwait(false) while polling.

for (var i = 0; i < 500 && !condition(); i++)
{
    await Task.Delay(20).ConfigureAwait(false);
}

[FlorianRappl]

Still failing. I don't think this is a timing issue.

[Copilot]

Still failing. I don't think this is a timing issue.

You're right—the timeout was not the cause. The queued delivery bypassed EngineInstance.RunTask, so EngineInstance.Current was unset while dispatching the frame's handler; its reply could be posted with the wrong sender context. I routed queued message delivery through the engine runner in 170f94f. The Windows CI job now passes.

[FlorianRappl]

LGTM!