What are slivers and when should you use them?

Slivers are low-level scrolling components that allow you to implement complex, custom scroll behaviors.

Unlike standard widgets that have fixed sizes, slivers lazily compute their size based on the scroll offset and viewport. You use CustomScrollView with Slivers (SliverList, SliverGrid, SliverAppBar) to create effects like collapsing headers, sticky headers, or heterogeneous scrolling lists.