Expose closed form destinations as they are discovered.

[jordwalke]

In addition to exposing an rAF throttled physics value callback, it would be extremely helpful to also include as much information as can be determined about the future values. This would look like:

• As your finger is released, the easing function, final destination and length of animation that will be started.
• Of course, if a touch or interaction occurs before the final time of animation being complete, that prior plan is invalidated - but applications can trivially handle that case.

The reason why this is important, is that we can compute CSS transition functions and keyframes (not just transforms) that execute very performantly - quite possibly the only way to move things on screen while being resilient to image decoding.

Please let me know if anyone has thought of a way to do this easily.