Optimized module loading for forking or non-forking processeshttp://search.cpan.org/dist/prefork
The "prefork" pragma is intended to allow module writers to optimise
module loading for both scenarios with as little additional code as
prefork.pm is intended to serve as a central and optional marshalling
point for state detection (are we running in compile-time or run-time
mode) and to act as a relatively light-weight module loader.