I want my sections in the UICollectionView
to have a header with an image.
I have followed these steps:
If you've got a generic subclass then you must take care to specify ObjC delegate method name if it's different then Swift name (https://bugs.swift.org/browse/SR-2817).
@objc (collectionView:viewForSupplementaryElementOfKind:atIndexPath:)
func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
...