I dont think thats actually possible...

what I think would happen is:

1. `_remove_backoff_block` would have to have been called in order to clear backoff state and actually send the `RDY 1`
2. 1 message comes in
3. `handle_message` would see that you're at `RDY 0` (and not in backoff state) and send `RDY N` based on `max_in_flight` and `num_conns`