Examples of widgets extending off-screen and various ways of handling this. Demos with "naive" in the title optimize nothing at all, and they probably shouldn't be used except in trivial cases. Other examples attempt various performance improvements.
Check out the live demo at: https://justinmc.github.io/flutter-lazy-performance/.
Thanks to the Marty McFly asset from Rive: https://rive.app/community/17-marty_v6/.
