How to pause an animation?

In my project I need to be able to pause an animation and continue from the same point of time. I struggle to to this with `Motion` and `spring`. This looks like the 'magic buttons' that were presented at the React-Europe talk (at least I think so), but I couldn't find their source code in the demos.

Start by locating the Motion and spring entry points and reviewing the React-Europe talk demos referenced in the issue. Determine how an animation can pause and resume at the same point; done means the behavior is implemented or documented with a reproducible example, but no source file or test is identified here.

Written by the indexing model from the issue text.