Atomic property wrapper in Swift

Atomic-propertyWrapper

@propertyWrapper
struct Atomic<Value> {
    
    var lock = os_unfair_lock_s()
    var _value: Value
    
    init(wrappedValue value: Value) {
       _value = value
    }
    
    var wrappedValue: Value {
        mutating get {
            os_unfair_lock_lock(&lock)
            defer {
                os_unfair_lock_unlock(&lock)
            }
            return _value
        }
        set {
            os_unfair_lock_lock(&lock)
            _value = newValue
            os_unfair_lock_unlock(&lock)
        }
    }
}