This module requires the service of mod_cache. It acts as a support module for
mod_cache and provides a memory based storage manager. mod_mem_cache can be
configured to operate in two modes: caching open file descriptors or caching
objects in heap storage. mod_mem_cache is most useful when used to cache
locally generated content or to cache backend server content for mod_proxy
configured for ProxyPass (aka reverse proxy).

Content is stored in and retrieved from the cache using URI based keys. Content
with access protection is not cached.