Uso UICollectionViewCompositionalLayout para crear UICollectionView, quiero que el primer elemento ocupe la mitad del ancho, otros elementos ocupen 1/4 del ancho, los elementos crecen hacia abajo, así:

https://i.stack.imgur.com/uO5R9.png

pero no puedo lograr la coexistencia de dos grupos en la sección, este es mi código:

 let compositionalLayout: UICollectionViewCompositionalLayout = { let inset: CGFloat = 1 // Items let largeItemSize = NSCollectionLayoutSize(widthDimension: .fractionalWidth(0.5), heightDimension: .fractionalHeight(1)) let largeItem = NSCollectionLayoutItem(layoutSize: largeItemSize) largeItem.contentInsets = NSDirectionalEdgeInsets(top: inset, leading: inset, bottom: inset, trailing: inset) let smallItemSize = NSCollectionLayoutSize(widthDimension: .fractionalWidth(0.5), heightDimension: .fractionalHeight(1)) let smallItem = NSCollectionLayoutItem(layoutSize: smallItemSize) smallItem.contentInsets = NSDirectionalEdgeInsets(top: inset, leading: inset, bottom: inset, trailing: inset) let smallItemGroupSize = NSCollectionLayoutSize(widthDimension: .fractionalWidth(1), heightDimension: .fractionalHeight(0.5)) let smallItemGroup = NSCollectionLayoutGroup.horizontal(layoutSize: smallItemGroupSize, subitems: [smallItem]) // Nested Group let nestedGroupSize = NSCollectionLayoutSize(widthDimension: .fractionalWidth(0.5), heightDimension: .fractionalHeight(1)) let nestedGroup = NSCollectionLayoutGroup.vertical(layoutSize: nestedGroupSize, subitems: [smallItemGroup]) // Outer Group let outerGroupSize = NSCollectionLayoutSize(widthDimension: .fractionalWidth(1), heightDimension: .fractionalWidth(0.5)) let outerGroup = NSCollectionLayoutGroup.horizontal(layoutSize: outerGroupSize, subitems: [largeItem, nestedGroup]) // Section let section = NSCollectionLayoutSection(group: outerGroup) section.contentInsets = NSDirectionalEdgeInsets(top: inset, leading: inset, bottom: inset, trailing: inset) // Supplementary Item let headerItemSize = NSCollectionLayoutSize(widthDimension: .fractionalWidth(1), heightDimension: .absolute(40)) let headerItem = NSCollectionLayoutBoundarySupplementaryItem(layoutSize: headerItemSize, elementKind: UICollectionView.elementKindSectionHeader, alignment: .top) section.boundarySupplementaryItems = [headerItem] let layout = UICollectionViewCompositionalLayout(section: section) return layout }()

https://i.stack.imgur.com/i88Q2.png

¿Cómo debo usar UICollectionViewCompositionalLayout para lograr el efecto de la Figura 1?