Cache-specific functionality

[lewisjkl]

I know that there have been discussions in the past about what to do when it comes to features that are specific to certain cache implementations. One approach to this is to just add the extra functions into the cache implementation classes themselves (i.e. RedisCache like in #348) without any common interface added into the AbstractCache.

Another option that I can think of is adding typeclasses that represent some of these more powerful cache features. Then any cache that is capable of supporting those features would just implement those typeclasses. The advantage I see here is that then you could program to the typeclass rather than a specific cache implementation and potentially still switch cache implementations down the line. The main downside I see is that this could get messy and the overlap between cache functionality may not be as much as I am assuming here.

In any case, would love to get some preliminary thoughts about those approaches as well as other ideas for what to do moving forward.