How to store, and restore animation states

I'm trying to implement a rewind function into the a game I'm working on. I've got it working now apart from correctly rewinding animations.

I want to store the state of an animation (which animation is playing, and the current point/frame of the animation) and then be able to restore that at a later point.

I've look through the docs at Animation and AnimationState but no ideas on how I'd do this yet.