Hi,

I've tried getting asynchronous annotations to work, and basically it
is a whole bunch of ...

I have gone through with an example backend of my own as well as with
vc-cvs (which inexplicably still works synchronously here), so both
the asynchronous as well as the synchronous operation should be
covered by now.

I am not sure I like the behavior when doing P or N or similar in the
annotation buffer: since the buffer is reused, it is cleared and
filled with new material while being displayed on the screen.

There are two ways around that, I guess.  One way would be to switch
back to the source buffer while the operation progresses.  Another way
would be to _not_ reuse the buffer but instead delete the old buffer
once the new one is complete.

Anyway, here is a patch regarding the current working state at my end.
Stefan, what do you say?

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum