I need to sync the vertical content offset for a tabBbar viewControllers. I accomplished this sending a notification on didScroll

func scrollViewDidScroll(_ scrollView: UIScrollView) {
    NotificationCenter.default.post(name: name, object: self, userInfo: ["offset": scrollView.contentOffset])
}

And the reading it back in viewDidLoad:

    NotificationCenter.default.addObserver(forName: name, object: nil, queue: .main) { notification in
        let offset = notification.userInfo!["offset"]! as! CGPoint

        if let sender = notification.object as? SyncedViewController, sender != self {
            self.collectionView.contentOffset = offset
        }
    }

Everything works as expected expect one big caveat, you need to tap on each tab in order this to work, otherwise it wont work 🙁

I also tried to force viewDidLoad using _ = vc.view but with no success.