on 'wrong thread' reinject packets to correct thread
While I'm reviewing (and of course at the same time cleaning up) the threading framework, I was thinking we could 'solve' the wrong-thread issue by reinjecting a packet into the correct thread. This would of course have a perf impact, likely a large one, but it might be a better 'failure mode' than just continuing in this known bad state. It would not be a 100% fix either, as packet order might still get messed up by this.
I suppose we could then disable further stream events for that flow, and maybe in general put it into some kind of 'liberal' state wrt stream engine checks.
We'd still increment wrong_thread counters and such, as the goal of a serious deployment should be to minimize that.