context_menu_preview_show.swift

func tableView(_ tableView: UITableView, willPerformPreviewActionForMenuWith configuration: UIContextMenuConfiguration, animator: UIContextMenuInteractionCommitAnimating) {
    guard let identifier = (configuration.identifier as? NSString) as String? else { return }
    let task = tasks.first { $0.id == identifier }
    if task != nil {
        animator.addCompletion {
            let previewController = TaskPreviewController()
            previewController.task = task
            self.show(previewController, sender: self)
        }
    }
}