Unrequested acks

According to XEP-0198:

"Either party MAY send an <a/> element at any time (e.g., after it has received a certain number of stanzas, or after a certain period of time), even if it has not received an <r/> element from the other party."

I can't seem to find a method to send an unrequested ack in Smack 4.1-alpha4, is this feature planned?