Animated speed preview for graph editor

I have just started looking into Tumult Hype, and it has a feature which I would love to see in After Effects. The graph editor has an animated line that gives you a preview of the speed of motion it will produce. It's a really quick way to preview the effect of adjustments before previewing in the composition. In the screenshot attached, the blue square is moving from bottom to top with the speed indicated by the graph curve. It can also be seen around 8:05 in this YouTube tutorial: https://www.youtube.com/watch?v=CDwKOhNC_Ag&t=485s