Code review comment for lp:~mir-team/mir/expose-debug-buffer-id-to-client

> For libmirclient we are providing stability, so a Mir update doesn't break
> mesa/XMir etc. Just mark functions as deprecated and we'll remove them in one
> big change (libmirclient1 -> libmirclient2). If you really want to get rid of
> a function now, then you have to bump ABI but this will probably be more work
> overall than just leaving the old function there.

I hope the same goes for protobuf too? (that we'll just clean up all dead code at once to minimize disruption). I'd feel better if this cleanup/old-api-breakage was scheduled at regular intervals or something (every three months perhaps), just so we keep bloat at a 3-month maximum.