Resource acquisition is initialization (RAII) in Swift: Example

DeinitBlock+URLImageTableViewCell.swift

class URLImageTableViewCell: UITableViewCell {
    @IBOutlet weak var urlImageView: UIImageView!    
    
    var urlImageLoader: DeinitBlock?

    // new task is created, old task cancelled automatically
    func setImage(url: URL) {
        urlImageLoader = urlImageView.setCachedImage(url: url)
    }
}