UICollectionView adds top margin

Question

I want to put a UICollectionView control that shows thumbs horizontally (only a single line of thumbs). For some reason the UICollectionView push the thumbs 44 pixels down,

Answer 1

Swift 5.2 / Xcode 11.3

viewController.automaticallyAdjustsScrollViewInsets 

has been deprecated since iOS 11.

My solution:

collectionView.contentInsetAdjustmentBehavior = .never