Return array of keys in storage

I was looking to use this on another project and I needed to get the list of keys in storage. This seemed like a core piece of functionality rather than writing a plugin for it.
Yes. I was wrestling with that issue before I submitted, but figured I would anyway to get the conversation going.

I think your suggestion is what I had rolling in my head. Definitely some more work, but does remove the duplication issue. I will head in that direction.