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public class NTPClient
    {
        protected internal DateTime GetNtpTime(int iUTCAdd)
        {
            //const string ntpServer = "time.nist.gov";
            const string ntpServer = "tick.stdtime.gov.tw";

            byte[] ntpData = new byte[48];
            
            //LeapIndicator = 0 (no warning), VersionNum = 3 (IPv4 only), Mode = 3 (Client Mode)
            ntpData[0] = 0x1B;
            
            IPAddress[] addresses = Dns.GetHostEntry(ntpServer).AddressList;
            IPEndPoint ipEndPoint = new IPEndPoint(addresses[0], 123);
            Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
            
            socket.Connect(ipEndPoint);
            socket.Send(ntpData);
            socket.Receive(ntpData);
            socket.Close();
            
            
            const byte serverReplyTime = 40;
            //Get the seconds part
            ulong intPart = BitConverter.ToUInt32(ntpData, serverReplyTime);
            
            //Get the seconds fraction
            ulong fractPart = BitConverter.ToUInt32(ntpData, serverReplyTime + 4);
            
            //Convert From big-endian to little-endian
            intPart = SwapEndianness(intPart);
            fractPart = SwapEndianness(fractPart);
            
            var milliseconds = (intPart * 1000) + ((fractPart * 1000) / 0x100000000L);
            
            //UTC time + 8 
            DateTime networkDateTime = (new DateTime(1900, 1, 1))
                .AddMilliseconds((long)milliseconds).AddHours(iUTCAdd);

            //UnityEngine.Debug.Log(networkDateTime);

            return networkDateTime;
        }
        
        // stackoverflow.com/a/3294698/162671
        uint SwapEndianness(ulong x)
        {
            return (uint)(((x & 0x000000ff) << 24) +
                          ((x & 0x0000ff00) << 8) +
                          ((x & 0x00ff0000) >> 8) +
                          ((x & 0xff000000) >> 24));
        }


        
    }