Can you explain the concept of lazy evaluation or deferred execution of tasks in programming?

Lazy evaluation is a programming technique where the computation of a value is deferred until it is actually needed. In iOS and Swift, this is often used to optimize performance and save resources.

For example, a property can be declared as lazy var, and its initialization will occur only upon the first access:

class DataLoader {
    lazy var data: [String] = {
        print("Loading data...")
        return ["One", "Two", "Three"]
    }()
}

let loader = DataLoader()
// Data is not loaded until loader.data is accessed
print(loader.data) // Initialization and output happen here

This is useful if the initialization is resource-intensive and may not be needed immediately or at all.