There's no need to keep asking -- this report was already rejected ;-)

Seriously, the efficiency argument carries no weight with me -- in 15
years of using Queue in a variety of applications, the time it takes to
.put and .get "here's a piece of work to do" descriptors is trivial
compared to the cost of /doing/ the "piece of work".  A Python-coded
subclass would have been plenty fast enough in any of those apps
(assuming I ever wanted to track a highwater mark, which to date I never
have).