The new `Handler` definition makes it harder to build state machines about russh HOT 2 CLOSED

There isn't any particular reason beyond simplification - it's unusual for a library to require this sort of a to-and-fro passing of the handler object, and it made method signatures complex and the logic of returning Self unobvious.

I suspect at least some of it is due to the old thrussh Handler design pre-async_trait.

The Handler interface is seems to be close enough to a state machine but actually doesn't safely map to it - a lot of it is just verbal agreement that some methods won't be called in some situations (e.g. auth_xxx won't happen after the connection is authenticated etc.), so writing a state machine Handler still requires you to manually check for these invariants.

But disregarding all that, you can actually still have the Handler be a FSM enum - you still can overwrite *self from the &mut self handler methods

from russh.

Okay, I see, thank you.

from russh.