ROS2: content-based topic subscriptions?

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Seeing as ROS2 will be using DDS as its middleware of choice, I was wondering if it would also support content filtered topic subscriptions next to the normal (ROS1) topic subscriptions.

Being able to filter messages on topics by content is a very powerful capability (especially with writer-side filtering), making bus-like topologies much more feasible in ROS applications without requiring each node to implement some kind of filtering mechanism itself.

Is this something that will be supported through the 'standard' ROS2-DDS API (I did not find anything in the design docs, but perhaps I've missed it), or will this require node implementors to bypass the API and reach into the underlying DDS implementation (if possible)?

The RTI community site has an example here.