Connection myNamespace::consConnection does not support optimized Pause/Resume. Optimized Pause/Resume requests will be converted to individual item Pause/Resume requests for this connection.
Connection myNamespace::consConnection does not support advanced symbol list. RFA will open data streams on behalf of client data stream request.
There is functionality within the RFA that can be implemented as part of the TREP or Elektron infrastructure or within the client itself. The notifications are to indicate that the infrastructure is not supporting such features so they are enabled in the API instead. Enabling in the API can mean additional CPU overheads when processing large number of instruments.
Advanced Symbol Lists support a feature whereby you can tell the provider to also send all constituents of the list as well as the list meta-data itself. This saves on the round trip times on the list meta-data and having to subscribe to each instrument separately.