RouterWire.swift

public protocol Router {
    associatedtype ViewController: UIViewController

    /// Returns view controller that is managing the view
    /// presented by the router
    var viewController: ViewController? { get }
}

extension Router {
    func wireNextRouter<T: Router>(_ wireClosure: @escaping (T.ViewController) throws -> T, file: StaticString = #file, line: UInt = #line) -> (UIViewController) -> Void {
        return { (targetViewController: UIViewController) -> Void in
            guard let target = targetViewController as? T.ViewController else {
                fatalError("Invalid target invoked: Should be \(T.ViewController.self), is \(type(of: targetViewController))", file: file, line: line)
            }

            do {
               _ = try wireClosure(target)
            } catch let error {
                fatalError("Error while instantiating \(T.self) at \(file):\(line): \(error)", file: file, line: line)
            }
        }
    }

    func wireEmpty() -> (UIViewController) -> Void {
        return { (targetViewController: UIViewController) -> Void in
        }
    }
}