Back port uniformAcrossSiblings for collection view compositional layout.

This is more of a request I hope y'all will consider.

Please back port uniformAcrossSiblings to iOS 13 (or maybe just 15?) (https://developer.apple.com/documentation/uikit/nscollectionlayoutdimension/4173072-uniformacrosssiblings)

It's like the iOS 9 UIStackView problem. Amazing new feature nobody can use.

Has anyone else done this themselves with either custom or subclass UICollectionViewCompositionalLayout?