static bool HttpResponse::setCache ( bool $cache )
Whether it should be attempted to cache the entity. This will result in necessary caching headers and checks of clients If-Modified-Since and If-None-Match headers. If one of those headers matches a 304 Not Modified status code will be issued. Note: If you're using sessions, be sure that you set session.cache_limiter to something more appropriate than "no-cache"!
Returns TRUE on success or FALSE on failure.