The randomly generated request ID that is sent with every message
to the RCON server. Used to ensure that the commands sent to and
received from the server are ours, and not another user's.
Starts listening on the socket for packets sent by the RCON server.
Returns a boolean that specifies if the socket has started listening.
Note: onData must accept a Uint8List as the only parameter. The payload
of the message starts at element 12.