Explain the difference between delegation mechanisms and KVO in the context of observing object changes.

Delegation mechanisms and KVO (Key-Value Observing) are different approaches to tracking changes in objects in iOS.

• Delegation is a pattern where one object (the delegate) implements a specific protocol and receives notifications about events or changes in another object. The delegate is explicitly assigned and is responsible for handling events.

• KVO is a mechanism that allows observing changes to property values of an object without the need to write explicit calls. The observer registers for a specific property, and the system automatically notifies it upon changes.

Example of delegation:

protocol MyDelegate: AnyObject {
    func didUpdateData()
}

class DataProvider {
    weak var delegate: MyDelegate?
    func update() {
        // data update
        delegate?.didUpdateData()
    }
}

Example of KVO:

class Person: NSObject {
    @objc dynamic var name: String = ""
}

let person = Person()
var observation = person.observe(
    \\Person.name, options: [.new]) { object, change in
    print("Name changed to \(change.newValue!)")
}
person.name = "John"

The main difference: delegation requires explicit calls to delegate methods, while KVO automatically tracks property changes without additional code at the change site.