IO::Event provides a object-based callback system for handling
nonblocking IO. The design goal is to provide a system that just does
the right thing w/o the user needing to think about it much.

All APIs are kept as simple as possible yet at the same time, all
functionality is accesible if needed. Simple things are easy. Hard
things are possible.

Most of the time file handling syntax will work fine: "<$filehandle>"
and "print $filehandle 'stuff'".

IO::Event provides automatic buffering of output (with a callback to
throttle). It provides automatic line-at-a-time input.

After initial setup, call "IO::Event::loop()".

IO::Event was originally written to use Event. IO::Event still defaults
to using Event but it can now use AnyEvent or its own event loop.