Swift Async Image Download

import UIKit

/* Reusable ID = "customCell" */
class CustomTableViewCell: UITableViewCell {
    var imageUrl: String!
    @IBOutlet weak var imageView: UIImageView!
    @IBOutlet weak var name: UILabel!
    .
    .
    .
}

class UIViewController: UITableDelegate, UITableDataSource {

    var people = [Person]() // populated at some point with person.name and person.imageUrl?
    .
    .
    .
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        if let cell = tableView.dequeueReusableCell(withIdentifier: "customCell") as? CustomTableViewCell {
            if let person = people[indexPath.row] {
                cell.name = person.name
                if let imageUrl = person.imageUrl {
                    cell.imageUrl = imageUrl
                    // Download image from URL asynchronously
                    URLSession.shared.dataTask(with: imageUrl) { data, response, error in
                        guard let data = data, error == nil else { return }
                        DispatchQueue.main.async() { () -> Void in
                            if cell.imageUrl == imageUrl { // If cell url still matches downloaded image url, set to imageView. Otherwise discard (or cache)
                                self.imageView.image = UIImage(data: data)
                            }
                        }
                    }.resume()
                }
            }
        }
    }
}