"Even though a client might be available (as stated in the most recent presence stanza), the user this client belongs to might not be focused on the client currently. Presence Obtained via Kinesthetic Excitation (POKE)  defines a method for a physical test of user presence. Since this requires special hardware that cannot be assumed to be available, this XEP defines a software-only implementation where no direct feedback is expected. This feature is known as 'nudge' or 'buzz' in some non-XMPP IM protocols.
It was discussed whether this feature belongs in Chat State Notifications . However, the semantics are inherently different, since Chat State Notifications describe the sender's state, not a request to change the receiver's. Thus, a separate extension is desirable."
Would it make sense to add this as a property (attention) in Message class?