AnyEvent provides an identical interface to multiple event loops.
This allows module authors to utilise an event loop without forcing
module users to use the same event loop (as only a single event loop
can coexist peacefully at any one time).

The interface itself is vaguely similar but not identical to the Event
module.

On the first call of any method, the module tries to detect the
currently loaded event loop by probing wether any of the following
modules is loaded: Coro::Event, Event, Glib, Tk. The first one found
is used. If none is found, the module tries to load these modules in
the order given. The first one that could be successfully loaded will
be used. If still none could be found, AnyEvent will fall back to a
pure-perl event loop, which is also not very efficient.

WWW: http://search.cpan.org/dist/AnyEvent/