The error handler shall no longer inform the user of a session-end trigger from the other side! Left alone this way, we've broken the whole system by introducing a chicken-egg paradox: We don't let our user be informed of the session-end trigger when would normally, so they won't call our dtor; but because they won't call our dtor, we'll never reach the point where the channel would get hosed and we'd know the inform the user. How to fix this? The answer is pretty obvious: Receiving the <code>GracefulSessio