State machine

[gselander]

Remaining issue from #354:

Discussion at IETF 115 (
https://datatracker.ietf.org/doc/minutes-115-lake-202211081630/):

MV: I volunteer to provide a first sketch of state machine for an
appendix.
DN: Maybe too optimistic. If the state machine in the figure is not
perfectly aligned with the specification, this will create problem.
GS: Can we give it a try with a sketch in an appendix, before
deciding to keep it or not?
SF: Yes, and we can have a quick check on the mailing list about
keeping it.

Just as an update on this, the current version of the state machine is at:

https://docs.google.com/presentation/d/1ai-ypkBlsjIhTjNglaMXsCqvgw99Lq8j9YrbAkSxgdg/edit

It’d be great to get comments on that.