There are a couple that are exposed in public interfaces.  Specifically, I refer to the singleton in serialization as well as the singleton in exposed in pool.  I understand that those in "detail" are hidden, but that would not prevent me from duplicating them in my own code if one particular implementation is considered a best-practice.

 

Thanks for that reference!  Singularity addresses one big issue I typically contend with regarding singletons--lifecycle--but the other cited issues (scope and initialization) are generally not issues for me.  The notion of "singularity" being an orthogonal attribute to so many others.