property Client: TIdCmdTCPClient;

Client is a read-only TIdCmdTCPClient property that represents the command handler-enabled client for the listening thread. 

Client is assigned the value passed as an argument to the Create constructor. Client is also used to create the TIdContext passed to command handlers in the client. 

During execution of the listening thread (in the protected Run method), Client is used to access its assigned command handlers and to access properties and methods in the IOHandler.