appdotnet/object-metadata — pull request #11 by amazingsyco (2013-02-26 19:19:52+00:00)
Title: Typing Presence annotation

Many private messaging apps (e.g. AIM, iMessage) supply the ability for clients to pass data about whether either user in a chat is currently typing. The client can either update the UI or do nothing. This annotation specifies if the user has started or stopped typing in a machine-only post to a channel.