Call out in Twitter Lite post

> Up until recently, we were using react-waypoint, which worked well for us. However, in chasing the best possible performance for one of the main underlying components of our application, it just wasn’t fast enough.

> Waypoints work by calculating many different heights, widths, and positions of elements in order to determine your current scroll position, how far from each end you are, and which direction you’re going. All of this information is useful, but since it’s done on every scroll event it comes at a cost: making those calculations causes jank–and lots of it.

https://medium.com/@paularmstrong/twitter-lite-and-high-performance-react-progressive-web-apps-at-scale-d28a00e780a3

Is it possible that we've fixed these problems or do they still exist and if so are they fixable?

cc @paularmstrong