[IRtdServer interface method] ServerStart(CallbackObject) [Description] 
This method is called when Excel requests the first topic from the real-time data server. This method returns a Long value; a value of 1 indicates a successful request, and a value of zero (0) or a negative value indicates a failed request. This method call is immediately followed by a call to the ConnectData method. The CallbackObject parameter is a required IRTDUpdateEvent callback object that the RTD server uses to notify Excel when it should gather updates from the RTD server through the IRTDUpdateEvent callback object's UpdateNotify method.