Use of "persistent storage" term

[Slakah]

Persistent store is a term which usually means storage of data which will not be lost after powering down, see: here or a google search.

Having a quick glance over the code I think this library stores data in memory, so I think it could be somewhat confusion.

Some candidates for alternatives:

• In-memory storage
• Store

Other suggestions welcome.

[rossabaker]

The verbiage comes from the Haskell library, but I agree that sends the wrong message. I like `"in-memory".