Swift autoclosure "lazy" evaluation

Autoclosures.swift

struct SomeStruct {
    init(someReallyExpensiveValue: @autoclosure () -> Int) {
        print("really expensive")
        Thread.sleep(forTimeInterval: TimeInterval(someReallyExpensiveValue() * 1))
    }

    init(someEvenMoreExpensiveValue: @autoclosure () -> Int) {
        print("even more expensive")
        Thread.sleep(forTimeInterval: TimeInterval(someEvenMoreExpensiveValue() * 5))
    }
}

func someFunction(
    a: @autoclosure () -> SomeStruct,
    b: @autoclosure () -> SomeStruct,
    useA: Bool
) {
    if useA {
        print(a())
    } else {
        print(b())
    }
}

someFunction(a: .init(someReallyExpensiveValue: 1), b: .init(someEvenMoreExpensiveValue: 1), useA: true)