It's useful to expose this bit of state because, although callers can keep track of it themselves, it's already in the Conversation so it seems wasteful to make them do so. R=golang-dev, ioerror CC=golang-dev https://golang.org/cl/6724056
R=golang-dev, r CC=golang-dev https://golang.org/cl/6446054
otr implements the Off-the-Record messaging protocol from http://www.cypherpunks.ca/otr/. It's often used on IRC and Jabber for private conversations. R=golang-dev, rsc, dchest CC=golang-dev https://golang.org/cl/6300064