UICollectionLayoutListConfiguration.HeaderMode.firstItemInSection
A header mode that styles the first item in a section as a header.
Declaration
case firstItemInSectionDiscussion
Choose this header mode when you’re using hierarchical data sources if you want to be able to expand and collapse the header.
When you use this header mode, a UICollectionViewListCell object that appears as the first item in the section automatically uses a header appearance. When you configure your data source, make sure to account for the fact that the first item in the section (at index 0) represents the header, and the actual items in the section start at index 1.
By default, lists that use the UICollectionLayoutListConfiguration.Appearance.plain and UICollectionLayoutListConfiguration.Appearance.sidebarPlain list appearances use pinned headers. If you want to opt into this default pinning behavior, use the UICollectionLayoutListConfiguration.HeaderMode.supplementary header mode instead.