apex::mixin::iterator needs a serious refactor #6
Description
The current apex::mixin::iterator type has been a disaster in terms of implementation. However a recent article brought some information to my attention. As a result we'll be killing apex::mixin::iterator and cannablizing it into the apex::mixin::iterable, as this name makes more sense.
However the work to get this implemented will take some time as we do not have a ranges implementation, nor do we have a fully working concepts implementation. As such, this will be minimal and underconstrained. This means code can be expected to break in the near future. However, code breaking means that the code was not correct in the first place, we just couldn't prevent bad code from being written.