RxExtensions4.swift

extension UIScrollView {
    func loadNextPageObservable() -> Observable<Void> {
        return rx.contentOffset
            .skipWhile {
                $0.y < self.frame.size.height
            }.map { contentOffset -> Bool in
                let padding = CGFloat(20.0)
                return contentOffset.y + self.frame.size.height + padding > self.contentSize.height
            }.distinctUntilChanged().map { shouldLoad in
                if shouldLoad {
                    Void()
                }
        }
    }
}