is there any plan to introduce where client can listen to data modification for some key?
some short of push notification which can notify client, instead of client does pull periodically.
I have use case where one client modifies data for the key but another client is not aware about change unless it queries it.
We have a slightly different thing in the near-term roadmap than what you asked. We are building a publication framework on top of XDR (which is an enterprise-only feature). The general idea is to send record update/delete event notifications via HTTP to an external web application. It will not be per key, but can the configured at set level. The web application will get the whole record or the changed bins based on configuration and it can take necessary action.