IO::Event provides an object-based callback system for handling nonblocking IO.
The design goal is to provide a system that just does the right thing without
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.