I am the developer of Supervisor (http://supervisord.org) which depends
on (and extends) Medusa 0.5.4, which itself depends on some
implementation details of pre-2.6 versions of asynchat (e.g.
"ac_out_buffer").

I need to make sure Supervisor works with Python 2.3, 2.4, and 2.5, as
well as Python 2.6.  To do so, I intend to just ship the Python 2.5
version of asyncore/asynchat along with Medusa 0.5.4 and Supervisor in
the next Supervisor release; straddling the asynchat stuff would just be
too hard here.

I don't know of any other consumers of Medusa other than Zope and
Supervisor, so maybe Medusa should just ship with its own version of
asyncore and asynchat forever from now on;  I'm certainly not going to
take the time to "fix" Medusa to forward port it to the 2.6 version of
asynchat.

I might argue that in retrospect the the current implementation of
asynchat might have been better named "asynchat2", as the changes made
to it seem to have broken of its major consumers.  But we can work
around it by just forking, I think.