A cache could be used instead of a multiplexer.
Check out: http://search.cpan.org/~petdance/WWW-Mechanize-Cached/Cached.pm
Caching would replace a multiplexer implementation
The implementation has been made some time ago. Some proper testing remains.
Use of WWW::Mechanize::Cached added and implemented.
Check out: http://search.cpan.org/~petdance/WWW-Mechanize-Cached/Cached.pm