In my testing (on Windows) fork() ended up using Threads.pm, which made IO::Socket::SSL break.

I am using threads, just not to do communication with clients.
The package which contains the multiplexing https server has a reference to a 'dispatcher' object with methods like:
* dispatcher->dispatch(headers,body)
* dispatcher->pending_responses()
* dispatcher->retrieve_response()
The dispatcher runs in a separate thread - and manages dispatch of "work" to a pool of worker threads via Thread::Queue::Any.

-David.