More Swift 4! In this tutorial, learn how to understand and properly implement delegation from scratch. Great tutorial to bookmark because, if you're like me, you have to reference something every time you delegate!
You'll also learn about creating a UML diagram, which Andrew says is the best tool he's found for designing object-oriented software. It's a great way to visualize what's happening.
I’ll show you how, through delegation, a UIViewController subclass can be notified by the helper that an image file has finished downloading, and then the view controller can display the image on screen.
Tutorial: delegates and delegation in Swift 4 by Andrew Jaffee