Data::Object::Role::Proxyable provides a wrapper around the AUTOLOAD routine
which processes calls to routines which don't exist. Adding a build_proxy method
to the consuming class acts as a hook into routine dispatching, which processes
calls to routines which don't exist. The build_proxy routine is called as a
method and receives $self, $package, $method, and any arguments passed to the
method as a list of arguments, e.g. @args. The build_proxy method must return a
routine (i.e. a callback) or the undefined value which results in a "method
missing" error.