C# code for waking up Xbox on UWP

XboxWakeupSharp.cs

public static async Task XboxWake(IPAddress ipAddress, string liveId, int retries = 5)
{
	using (var socket = new DatagramSocket())
	{
		var connectionProfile = Windows.Networking.Connectivity.NetworkInformation.GetInternetConnectionProfile();
		await socket.BindServiceNameAsync("", connectionProfile.NetworkAdapter);

		using (var stream = await socket.GetOutputStreamAsync(new HostName(ipAddress.ToString()), "5050"))
		{
			using (var writer = new DataWriter(stream))
			{
				for (int retry = 0; retry < retries; retry++)
				{
					byte[] payload = new byte[3 + liveId.Length];
					payload[0] = 0x00;
					payload[1] = (byte)liveId.Length;

					for (int i = 0; i < liveId.Length; i++)
						payload[i + 2] = (byte)liveId[i];
					payload[payload.Length - 1] = 0x00;

					byte[] header = new byte[6];
					header[0] = 0xdd;
					header[1] = 0x02;
					header[2] = 0x00;
					header[3] = (byte)payload.Length;
					header[4] = 0x00;
					header[5] = 0x00;

					using (var ms = new MemoryStream(header.Length + payload.Length))
					{
						ms.Write(header, 0, header.Length);
						ms.Write(payload, 0, payload.Length);

						writer.WriteBytes(ms.ToArray());
					}
					await writer.StoreAsync();

					await Task.Delay(1000);
				}
			}
		}
	}
}