Can you explain the concept of delegation in design patterns and how it is applied?

Delegation is a design pattern in which one object passes the execution of a specific task to another object, called a delegate. This allows for responsibility sharing and increases code flexibility.

In iOS, delegation is often used to pass events or data between objects. For example, UITableView uses a delegate to handle cell selection or appearance customization.

Example in Swift:

protocol MyDelegate: AnyObject {
    func didFinishTask()
}

class Worker {
    weak var delegate: MyDelegate?

    func startTask() {
        // Perform the task
        // ...
        delegate?.didFinishTask()
    }
}

class Manager: MyDelegate {
    func didFinishTask() {
        print("Task completed")
    }
}

let worker = Worker()
let manager = Manager()
worker.delegate = manager
worker.startTask()

Here, the Worker object delegates the notification of task completion to the Manager object.