LWP::UserAgent with caching based on CHI

 LWP::UserAgent::CHICaching is yet another caching user agent. When the
 client makes a request to the server, sometimes the response should be
 cached, so that no actual request has to be sent at all, or possibly
 just a request to validate the cache. HTTP 1.1 defines how to do this.
 This class simply extends LWP::UserAgent with
 LWP::UserAgent::Role::CHICaching (also in this distribution) which is
 doing the real work to make it possible to use the very flexible CHI
 module to manage such a cache.