Static variables in template class results in smart enqueuer-dequeuer pattern.

Decorator pattern[1] tricks to reduce queue dependency

TL;DR this one simple trick for static member initialization in a class template[2].

The original rather dumb enqueuer and dequeuer used the shared_queue class to track their counts and close the underlying queue accordingly. Giving them each their own static count makes the shared_queue wrapper redundant and usage more intuitive, but how to initialise the static variable was a brief head scratcher...

Smart dequeuer decorator:

References:
[1] http://en.wikipedia.org/wiki/Decorator_pattern
[2] static member initialization in a class template