应用离线30秒后使用NSURL发布请求

如何解决应用离线30秒后使用NSURL发布请求

当我离线并进入后台应用程序超过30秒时，我在发送消息时遇到问题，直到我再次进入该应用程序时，消息才会发送。

我已在Apple开发者论坛上发布了此问题：https://developer.apple.com/forums/thread/656778

有人告诉我，我需要使用NSUrlSession解决该问题，

但是在这里我很困惑我需要实现什么功能。

我尝试了这段代码，但是没有用

func postAction(_ sender: Any) {
    let Url = String(format: "your url")
    guard let serviceUrl = URL(string: Url) else { return }
    let parameterDictionary = ["username" : "Test","password" : "123456"]
    var request = URLRequest(url: serviceUrl)
    request.httpMethod = "POST"
    request.setValue("Application/json",forHTTPHeaderField: "Content-Type")
    guard let httpBody = try? JSONSerialization.data(withJSONObject: parameterDictionary,options: []) else {
        return
    }
    request.httpBody = httpBody

    let session = URLSession.shared
    session.dataTask(with: request) { (data,response,error) in
        if let response = response {
            print(response)
        }
        if let data = data {
            do {
                let json = try JSONSerialization.jsonObject(with: data,options: [])
                print(json)
            } catch {
                print(error)
            }
        }
        }.resume()
}