Fundamentals of Callbacks for Swift Developers

This article provides a foundational understanding of callbacks for Swift developers, focusing on Swift 3.0. It defines callbacks as a common programming pattern in iOS development, explaining how they enable asynchronous programming to improve app performance and responsiveness. Using a practical example of designing an API for an ImageSketcher type, the article illustrates how callbacks allow developers to decouple the start and end of processes, such as generating an animated sketch, and hook back in with custom logic upon completion. It covers key concepts like API design, asynchronous tasks, and handling completion events, making it useful for developers learning iOS development patterns.