responderChain.swift

class SomeCustomViewController: UIViewController {
    override var next: UIResponder? {
        get {
            return nil
        }
        set {
            return
        }
    }
}

class SomeOtherCustomViewController: UIViewController {
    override var next: UIResponder? {
        return nil
    }
}

let controller = SomeCustomViewController()
let otherController = UIViewController()
controller.next = otherController