This example shows how to use `AnimationController` and
`SlideTransition` to create an animated digit like you might find on a
digital clock. New digit values slide into place from below, as the old
value slides upwards and out of view. Taps that occur while the
controller is already animating cause the controller's
`AnimationController.duration` to be reduced so that the visuals don't
fall behind.
You can try the example here:
https://dartpad.dev/?id=9553c20fe0fdb0c5447c1293e02400eb
