This module does two things differently to the venerable
Class::Accessor::Fast:

- Fields are stored at arms-length within a single hash value of $self, rather
  than directly in the $self blessed referent.

- new() allows mixin into an existing object, rather than creating and
  returning a new blessed hashref.

WWW: http://search.cpan.org/dist/Class-Accessor-Fast-Contained/