ResultCache impl for extensions of DataConnector

[Cantor, Scott]

> And there is an odd sorta-philosophical question as well given that 3.4 is the
> last release pre V4 (when APIs will change):  Is it worth changing anything in 3.4?
> 
> 	Customer uses impl now -> it might break at any time
> 	Customer uses Api in 3.4 -> it might break in V4
> 
> With the only difference being that we are more likely to take care about api
> breakages (and avoid them as much as possible).

That's why I'd rather wait on them so we can take any time needed to adjust things so it's stable going forward. The original design of all those classes may or may not have been thought about from the point of view of a public API. I definitely had problems adapting the HTTP connector to them though it's an unusual case perhaps.

-- Scott