Restart the server, terminating all active client connections
A value of zero is returned if the server was restarted,
otherwise a non-zero error code is returned which indicates the cause
of the failure.
The Restart method terminates all active client
connections, recreates a new listening socket bound to the same
address and port number, and then resumes accepting new client
connections. The OnDisconnect event will not fire for those
client sessions that are terminated when the server is restarted.