LeConnectionOrientedChannel enters invalid state in race condition

[whitevegagabriel]

LeConnectionOrientedChannel has a race condition:

1. Call disconnect and enter state DISCONNECTING
2. Receive on_disconnection_request and enter state DISCONNECTED
3. Receive on_disconnection_response and see that state is not DISCONNECTING, log invalid state and return

Not sure what the best solution is here, but it seems valid (though unlikely) that one might receive a disconnection request before disconnect is done processing.

[barbibulle]

Thanks for reporting this. It definitely looks like a race condition that should be avoided. I'll push a PR shortly.