UITableViewExtensions.swift

import RxSwift

extension UITableView {
   var rxex_nextPageTriger:Observable<Void> {
      return self
         .rx_contentOffset
         .flatMapLatest { [unowned self] (offset) -> Observable<Void> in
            let shouldTriger = offset.y + self.frame.size.height + 40 > self.contentSize.height
            return shouldTriger ? just() : empty()
      }
   }
}