MCE::Inbox lives on Github, currently. Depending on whether threads is loaded, it will configure channels using Thread::Queue or MCE::Shared::Queue otherwise. There are examples demonstrating "Chameneos, a Concurrency Game for Java, Ada, and Others" using Perl over here.
I will make a MCE::Inbox release on CPAN after MCE 1.834 and MCE::Shared 1.835. These provide a fix on Microsoft Windows so that dequeue doesn't involve checking the socket each time if ready. On Windows, I figured a way so that nested-sessions may continue to work and not degrade dequeue performance from Perl 5.20 and up. Basically, workers spawning workers or workers exiting while other workers dequeue items from a queue.