在Swift3中并行保存多个PFFiles

import Dispatch

// 创建一个DispatchGroup
let group = DispatchGroup()

// 创建一个并发队列
let queue = DispatchQueue(label: "com.example.queue", attributes: .concurrent)

// 创建多个任务，每个任务保存一个PFFile
let file1 = PFFile(name: "file1", data: data1)
let file2 = PFFile(name: "file2", data: data2)
let file3 = PFFile(name: "file3", data: data3)

// 将任务添加到DispatchGroup中
group.enter()
queue.async {
    file1.saveInBackground { (success, error) in
        if success {
            print("File 1 saved successfully")
        } else {
            print("Error saving file 1: \(error?.localizedDescription ?? "")")
        }
        group.leave()
    }
}

group.enter()
queue.async {
    file2.saveInBackground { (success, error) in
        if success {
            print("File 2 saved successfully")
        } else {
            print("Error saving file 2: \(error?.localizedDescription ?? "")")
        }
        group.leave()
    }
}

group.enter()
queue.async {
    file3.saveInBackground { (success, error) in
        if success {
            print("File 3 saved successfully")
        } else {
            print("Error saving file 3: \(error?.localizedDescription ?? "")")
        }
        group.leave()
    }
}

// 等待所有任务完成
group.wait()

// 所有任务完成后的操作
print("All files saved successfully")