RxSwift UIScrollView loadMore

UIScrollView+loadMore.swift

extension Reactive where Base: UIScrollView {
    var loadMore: Observable<Void> {
        return contentOffset
            .map({ [weak base] (offset) in
                guard let scrollView = base else { return false }
                return offset.y + scrollView.bounds.size.height - scrollView.adjustedContentInset.bottom >= scrollView.contentSize.height
            })
            .distinctUntilChanged()
            .filter({ $0 })
            .mapTo(Void())
    }
}