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Tae Hyung Kim authored
This widget implements the ability to place slivers one after another in a single ScrollView in a way that all child slivers are drawn within the bounds of the group itself (i.e. SliverPersistentHeaders aren't drawn outside of the scroll extent provided by all of the child slivers). The design document for SliverMainAxisGroup can be found [here](https://docs.google.com/document/d/1e2bdLSYV_Dq2h8aHpF8mda67aOmZocPiMyjCcTTZhTg/edit?resourcekey=0-Xj2X2XA3CAFae22Sv3hAiA). Fixes https://github.com/flutter/flutter/issues/33137. ## Pre-launch Checklist - [x] I read the [Contributor Guide] and followed the process outlined there for submitting PRs. - [x] I read the [Tree Hygiene] wiki page, which explains my responsibilities. - [x] I read and followed the [Flutter Style Guide], including [Features we expect every widget to implement]. - [x] I signed the [CLA]. - [x] I listed at least one issue that this PR fixes in the description above. - [x] I updated/added relevant documentation (doc comments with `///`). - [x] I added new tests to check the change I am making, or this PR is [test-exempt]. - [x] All existing and new tests are passing. If you need help, consider asking for advice on the #hackers-new channel on [Discord]. <!-- Links --> [Contributor Guide]: https://github.com/flutter/flutter/wiki/Tree-hygiene#overview [Tree Hygiene]: https://github.com/flutter/flutter/wiki/Tree-hygiene [test-exempt]: https://github.com/flutter/flutter/wiki/Tree-hygiene#tests [Flutter Style Guide]: https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo [Features we expect every widget to implement]: https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo#features-we-expect-every-widget-to-implement [CLA]: https://cla.developers.google.com/ [flutter/tests]: https://github.com/flutter/tests [breaking change policy]: https://github.com/flutter/flutter/wiki/Tree-hygiene#handling-breaking-changes [Discord]: https://github.com/flutter/flutter/wiki/Chat --------- Co-authored-by: Kate Lovett <katelovett@google.com>