public async Task Rotate(double angle)
{
if (IsBusy)
{
throw new InvalidOperationException();
}
IsBusy = true;
short angleShort = (short)(angle / Math.PI * 180);
byte[] packet = new byte[4];
packet[0] = Magic;
packet[1] = RotateCmd;
MyBitConverter.GetBytesBE(angleShort).CopyTo(packet, 2);
await WriteSerialAsync(packet, 0, packet.Length);
await ReceiveAcknowledgment();
Angle += angle;
IsBusy = false;
}