Add Callback handler based on partition key, so polling is not needed/charged RUs
ChangeFeedProcessorBuilder does not support subscribing only to certain PartitionKeys, so it'd be great if you supported that.
If not, I can get by with GetChangeFeedIterator and manual polling (pull model), but that's in preview, so please release that officially.
I believe even in #1, we are charged RUs for polling behind the scenes (correct me if I'm wrong.) So idle host instances are constantly consuming RUs. Is it possible to trigger Cosmos to call the registered callback handler only when something happens on the change feed --for the specified partition key. A trigger replaces polling. Then only charge RUs for the handler actually reading the feed. Eliminating polling RUs.
Thank you while we reviewed your request.
We have no plans on adding the capability you have asked for #3. We will review this in the future and update if our plans change.