+ * Whether it sould be attempted to cache the entitity.
+ * 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 shure that you set session.cache_limiter
+ * to something more appropriate than "no-cache"!