cell_provider.swift

 extension CollectionViewController {
     private func cellProvider(_ collectionView: UICollectionView, _ indexPath: IndexPath, _ item: Item) -> UICollectionViewCell? {
        
        guard let cell = collectionView.dequeueReusableCell(withReuseIdentifier: HostingControllerCollectionViewCell<AnyView>.reuseIdentifier, for: indexPath) as? HostingControllerCollectionViewCell<AnyView> else {
            fatalError("Could not load cell")
        }
        
        cell.host(content(indexPath, item))
        cell.backgroundColor = .green
        
        return cell
    }
    
}