      *  @param charset The character set encoding to use while encoding the
      *  credentials. The default is null, which implies the legacy charset of
      *  ISO-Latin-1. The only other supported charset is &quot;UTF-8&quot;.
+     *
+     *  @return Returns a token that client code may add a responder to in order to handle
+     *  success or failure directly.
      * 
      *  @throws flash.errors.IllegalOperationError in two situations; if the ChannelSet is
      *          already authenticated, or if a login or logout operation is currently in progress.

            }
            _clustered = value;
        }
    }
    
    //----------------------------------

            if (!_hasRequestedClusterEndpoints && clustered)
            {            
                var msg:CommandMessage = new CommandMessage();
                // Fetch failover URIs for the correct destination.
                if (agent is AuthenticationAgent)
                {
                    msg.destination = initialDestinationId;
                }
                else
                {
                    msg.destination = agent.destination;
                }
                msg.operation = CommandMessage.CLUSTER_REQUEST_OPERATION;
                _currentChannel.sendClusterRequest(new ClusterMessageResponder(msg, this));    
                _hasRequestedClusterEndpoints = true;                           
