var request = URLRequest(url: URL(string: "https://api.thingspeak.com/update")!)
        request.httpMethod = "POST"
        let postString = "api_key=H3MQFPAJ1IOK1I0W&field1=2"
        request.httpBody = postString.data(using: .utf8)
        let task = URLSession.shared.dataTask(with: request) { data, response, error in
            guard let data = data, error == nil else {
                print("error=\(error)")
                return
            }

            if let httpStatus = response as? HTTPURLResponse, httpStatus.statusCode != 200 {
                print("statusCode should be 200, but is \(httpStatus.statusCode)")
                print("response = \(response)")
            }

            let responseString = String(data: data, encoding: .utf8)
            print("responseString = \(responseString)")
        }
        task.resume()