Looks like I found the answer myself:
byte[] result = new byte[deviceToken.Length];
Marshal.Copy(deviceToken.Bytes, result, 0, (int) deviceToken.Length);
var token = BitConverter.ToString(result).Replace("-", "");
Using this code I was able to get a device token and send a notification.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…