POE::Session::MultiDispatch is a drop in replacement for POE::Session
that adds callback dispatch functionality to POE sessions.  Each event
may have multiple handlers associated with it.  Fine control over the
order of execution is available using helper methods that extend the
interface of a POE::Session.

POE::Session::MultiDispatch uses POE::Session as a base class.  When
multiple callbacks are registered for an event, only the last callback
survives, all the others are clobbered.  POE::Session::MultiDispatch is
much nicer to your registered callbacks, it keeps them all in the order
they were defined.  When an event is triggered, all the callbacks are
then executed in that same order (unless you muck around with said
order).