如何在没有NSURLSession的情况下在Swift中下载.zip文件？

import Foundation

func downloadZipFile() {
    guard let url = URL(string: "https://example.com/file.zip") else {
        print("无效的URL")
        return
    }
    
    let task = URLSession.shared.dataTask(with: url) { (data, response, error) in
        if let error = error {
            print("下载失败：\(error.localizedDescription)")
            return
        }
        
        guard let data = data else {
            print("无效的数据")
            return
        }
        
        // 将下载的数据保存到本地
        let fileURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first?.appendingPathComponent("file.zip")
        do {
            try data.write(to: fileURL!)
            print("下载完成：\(fileURL!)")
        } catch {
            print("保存文件失败：\(error.localizedDescription)")
        }
    }
    
    task.resume()
}

downloadZipFile()