Split from https://github.com/flutter/flutter/pull/122664 so it gets easier to review, as this is now unrelated to the `preferRound`. I'm one step from adding a width attribute, lol.

<img width="474" alt="image" src="https://user-images.githubusercontent.com/351125/226083798-71e529e9-4ae9-41de-a500-0412b989a273.png">

cc @Piinks