хм, пишу верно
Код:
_writer.Write(packet.Direction == Direction.ToServer ? 'C' : 'S');
_writer.Write("MSG".ToCharArray());
_writer.Write(ConnectionId);
_writer.Write(packet.TickCount);
_writer.Write(1);
_writer.Write(packet.Data.Length);
_writer.Write((byte) 1);
_writer.Write(packet.Data);