pg_worker and notify

Applications using postgres frequently require central process serializing
specific tasks. We usually implement these with external programs but the
reliability of such solution depends on a complexity that require carefull
monitoring.
I imagne an extension that would lauch some bg_workers waiting for notify
statements like:
NOTIFY <channel> <event>;
and for each <event> catched on the <channel>, calling calling a pl/pgsql
function with a single parameter <event>.
A predetermined list of bg_workers would be described in a public table in
the postgres database, and red at postgres startup. I wonder how to code a
bg_worker waiting for notifications on a channel. Have you any idea on such
implementation?

--
Olivier Chaussavoine
openbarter.org