class ViewController: UIViewController {
    
    var menuViewController: PagingMenuViewController!
    var contentViewController: PagingContentViewController!

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if let vc = segue.destination as? PagingMenuViewController {
            menuViewController = vc
        } else if let vc = segue.destination as? PagingContentViewController {
            contentViewController = vc
        }
    }

import UIKit
import PagingKit

class MenuCell: PagingMenuViewCell {
    @IBOutlet weak var titleLabel: UILabel!
}

class ViewController: UIViewController {
    
    var menuViewController: PagingMenuViewController!
    var contentViewController: PagingContentViewController!

    override func viewDidLoad() {
        super.viewDidLoad()
        
        menuViewController.register(nib: UINib(nibName: "MenuCell", bundle: nil), forCellWithReuseIdentifier: "MenuCell")
        menuViewController.registerFocusView(nib: UINib(nibName: "FocusView", bundle: nil))
    }

class ViewController: UIViewController {
    static var viewController: (UIColor) -> UIViewController = { (color) in
       let vc = UIViewController()
        vc.view.backgroundColor = color
        return vc
    }
    
    var dataSource = [(menuTitle: "test1", vc: viewController(.red)), (menuTitle: "test2", vc: viewController(.blue)), (menuTitle: "test3", vc: viewController(.yellow))]

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if let vc = segue.destination as? PagingMenuViewController {
            menuViewController = vc
            menuViewController.dataSource = self // <- set menu data source
        } else if let vc = segue.destination as? PagingContentViewController {
            contentViewController = vc
        }
    }
}

extension ViewController: PagingMenuViewControllerDataSource {
    func numberOfItemsForMenuViewController(viewController: PagingMenuViewController) -> Int {
        return dataSource.count
    }
    
    func menuViewController(viewController: PagingMenuViewController, widthForItemAt index: Int) -> CGFloat {
        return 100
    }
    
    func menuViewController(viewController: PagingMenuViewController, cellForItemAt index: Int) -> PagingMenuViewCell {
        let cell = viewController.dequeueReusableCell(withReuseIdentifier: "MenuCell", for: index) as! MenuCell
        cell.titleLabel.text = dataSource[index].menuTitle
        return cell
    }
}

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if let vc = segue.destination as? PagingMenuViewController {
            menuViewController = vc
            menuViewController.dataSource = self
        } else if let vc = segue.destination as? PagingContentViewController {
            contentViewController = vc
            contentViewController.dataSource = self // <- set content data source
        }
    }
}

extension ViewController: PagingContentViewControllerDataSource {
    func numberOfItemsForContentViewController(viewController: PagingContentViewController) -> Int {
        return dataSource.count
    }
    
    func contentViewController(viewController: PagingContentViewController, viewControllerAt index: Int) -> UIViewController {
        return dataSource[index].vc
    }
}

    override func viewDidLoad() {
        super.viewDidLoad()
        //...
        //...
        menuViewController.reloadData()
        contentViewController.reloadData()
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if let vc = segue.destination as? PagingMenuViewController {
            menuViewController = vc
            menuViewController.dataSource = self
            menuViewController.delegate = self // <- set menu delegate
        } else if let vc = segue.destination as? PagingContentViewController {
            contentViewController = vc
            contentViewController.dataSource = self
        }
    }
}

extension ViewController: PagingMenuViewControllerDelegate {
    func menuViewController(viewController: PagingMenuViewController, didSelect page: Int, previousPage: Int) {
        contentViewController.scroll(to: page, animated: true)
    }
}

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if let vc = segue.destination as? PagingMenuViewController {
            menuViewController = vc
            menuViewController.dataSource = self
            menuViewController.delegate = self
        } else if let vc = segue.destination as? PagingContentViewController {
            contentViewController = vc
            contentViewController.dataSource = self
            contentViewController.delegate = self // <- set content delegate
        }
    }
}

extension ViewController: PagingContentViewControllerDelegate {
    func contentViewController(viewController: PagingContentViewController, didManualScrollOn index: Int, percent: CGFloat) {
        menuViewController.scroll(index: index, percent: percent, animated: false)
    }
}

    let items = PublishSubject<[(menu: String, width: CGFloat, content: UIViewController)]>()

    override func viewDidLoad() {
        super.viewDidLoad()
        
        menuViewController?.register(type: TitleLabelMenuViewCell.self, forCellWithReuseIdentifier: "identifier")
        menuViewController?.registerFocusView(view: UnderlineFocusView())
        
        // PagingMenuViewControllerDataSource
        items.asObserver()
            .map { items in items.map({ ($0.menu, $0.width) }) }
            .bind(to: menuViewController.rx.items(
                cellIdentifier: "identifier",
                cellType: TitleLabelMenuViewCell.self)
            ) { _, model, cell in
                cell.titleLabel.text = model
            }
            .disposed(by: disposeBug)
        
        // PagingContentViewControllerDataSource
        items.asObserver()
            .map { items in items.map({ $0.content }) }
            .bind(to: contentViewController.rx.viewControllers())
            .disposed(by: disposeBug)
        
        // PagingMenuViewControllerDelegate
        menuViewController.rx.itemSelected.asObservable().subscribe(onNext: { [weak self] (page, prev) in
            self?.contentViewController.scroll(to: page, animated: true)
        }).disposed(by: disposeBug)
        
        // PagingContentViewControllerDelegate
        contentViewController.rx.didManualScroll.asObservable().subscribe(onNext: { [weak self] (index, percent) in
            self?.menuViewController.scroll(index: index, percent: percent, animated: false)
        }).disposed(by: disposeBug)
    }