prefetchRowsAt.swift

override func viewDidLoad() {
    super.viewDidLoad()
    
    tableView.prefetchDataSource = self
  }
  
// MARK: - Table View Data Source Prefetching
extension UsersTableViewController: UITableViewDataSourcePrefetching {
  func tableView(_ tableView: UITableView, prefetchRowsAt indexPaths: [IndexPath]) {
    print("prefetch rows at index paths: \(indexPaths)")
    if indexPaths.contains(where: isLoadingCell) {
      fetch()
    }
  }
}