TelnetThread is an instance of
TIdTelnetReadThread that is used to read data and commands for the
TIdTelnet object. All data from the host is read using this thread. The
OnDataAvailable and
OnTelnetCommand event handlers are called as a result of data being received via this thread.
TelnetThread is created when the client connects to the host, and terminated when the client disconnects from the host.