我使用翠鸟下载和设置图像imageviews在细胞中的imagableView。一切正常，在下载新图像之前，tableview首先显示占位符图像。但是，只有在滚动表视图后，这些占位符图像才会更新为正确的图像。如何在下载图像后立即更新单元格？谢谢

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

    let cell = articlesTableView.dequeueReusableCell(withIdentifier: "articleCell", for: indexPath) as! ArticleCell

    let resource = self.articlesArray?[indexPath.item].downloadedImageResource
        //resources are being downloaded using Kingfisher when populating the articlesArray and added to this array

    cell.picView.kf.setImage(with: resource, placeholder: #imageLiteral(resourceName: "LS_logo_male")){ (image, error, cacheType, imageUrl) in
        cell.setNeedsLayout()
    }

    return cell
}