The SliverDecoration widget introduced in PR #107269 is not finished and has at least the following issues:

1. It doesnt work in horizontal scrollviews
2. It uses the paintExtent of the child which isn't always the correct value to use, take for instance this example when applying a rounde corner. The bottom two corners shouldn't be rounded yet.

3. Overlap and other advanced properties of slivers aren't accounted for.
4. The name is inconsistent with the box counterpart DecoratedBox, this should be called DecoratedSliver. The current name suggests its the configuration just like BoxDecoration

The correct behaviour should be the same as using a SliverStack from sliver_tools with a SliverPositioned.fill behind the second child sliver.

Minimal repro example I can add later if needed (dont have time right now).

Proposed resolution steps

1. Revert [framework] SliverDecoration #107269 ✅
2. Discuss here what sliver features the finished implementation should and shouldnt support
3. Create extensive widget tests for those cases and reimplement

@Piinks @jonahwilliams FYI