Wrapper for embedding UIViewController in SwiftUI app.

Pack.Swift

//MARK:- Packs the UIKit's ViewController in SwiftUI View.
public struct Pack<Packed: UIViewController> : UIViewControllerRepresentable {

    public typealias Updater = (Packed, Context) -> Void

    //two closures for each of the method requirement of UIViewControllerRepresentable
    public var makeViewController: () -> Packed
    public var updateViewController: Updater
    
    //autoclosure here creates the viewcontrollers lazily, @escaping to preserve the closure to execute asynchronously
    init(_ makeViewController: @escaping @autoclosure () -> Packed, updateViewController:  @escaping Updater) {
        self.makeViewController = makeViewController
        self.updateViewController = updateViewController
    }

    public func makeUIViewController(context: Context) -> Packed {
        return makeViewController()
    }

    public func updateUIViewController(_ uiViewController: Packed, context: Context) {
        updateViewController(uiViewController, context)
    }
}

//MARK:- convinence initilazers
extension Pack {

    // only viewController as argument.
    public init(_ makeViewController: @escaping @autoclosure () -> Packed) {
        self.makeViewController = makeViewController
        self.updateViewController = { _ , _ in }
    }

    // viewcontroller without context as argument.
    public init(_ makeViewController: @escaping @autoclosure () -> Packed , updateViewController: @escaping (Packed) -> Void ) {
        self.makeViewController = makeViewController
        self.updateViewController = { viewController, _ in updateViewController(viewController) }
    }
}