Caching frequently requested files that change very infrequently is a technique
for reducing server load. mod_file_cache provides two techniques for caching
frequently requested static files.

Through configuration directives, you can direct mod_file_cache to either open
then mmap()a file, or to pre-open a file and save the file's open file handle.
Both techniques reduce server load when processing requests for these files by
doing part of the work (specifically, the file I/O) for serving the file when
the server is started rather than during each request.

Notice: You cannot use this for speeding up CGI programs or other files which
are served by special content handlers. It can only be used for regular files
which are usually served by the Apache core content handler.

This module is an extension of and borrows heavily from the mod_mmap_static
module in Apache 1.3.