TransitionMotion animated conditionally [question]

Hello everyone. I've been playing around with `react-motion` for the last couple of days and it's been a pretty intensive relation so far 😭 . I'd very much appreciate some guidance on when to use `Motion` vs `TransitionMotion` or why my use case, which I believe is quite common, is giving me this much struggle.

First, let me explain what I am trying to achieve. My use case is a **pane that appears from the right** with information about a point on a map that you just clicked. What I want to _conditionally_ animate is the enter animation, so that when you click on another point in the map and **the pane is already in place it won't animate from the beginning again**.

I'm new to the library and went ahead and started using `TransitionMotion` because my use case seemed to apply to the _Helps you to do mounting and unmounting animation_ premise.

I thought `onRest` would allow me to set a `shouldAnimate` flag in my component's inner state when the enter animation finishes so it happens only once, but since it is implemented in `Motion` and not in `TransitionMotion` I got kind of lost. Why is it not implemented? Is it not necessary because there is already a way to do this?

Mainly I'm wondering if I should be using `Motion` instead just because of that feature. But I'm not sure 😁 and the difference between the two is still blurry to me. Hopefully someone can point me in the right direction.

Thanks for your time 👋