Mason callback support via Params::CallbackRequest

 MasonX::Interp::WithCallbacks subclasses HTML::Mason::Interp in order to
 provide a Mason callback system built on Params::CallbackRequest.
 Callbacks may be either code references provided to the new() constructor,
 or methods defined in subclasses of Params::Callback. Callbacks are triggered
 either for every request or by specially named keys in the Mason request
 arguments, and all callbacks are executed at the beginning of a request, just
 before Mason creates and executes the request component stack.
 .
 This module brings support for a sort of plugin architecture based on
 Params::CallbackRequest to Mason. Mason then executes code before executing
 any components. This approach allows you to carry out logical processing of
 data submitted from a form, to affect the contents of the Mason request
 arguments (and thus the %ARGS hash in components), and even to redirect or
 abort the request before Mason handles it.