In stream delivery the debounce editor's stop() cleared the pending timer but
returned immediately even with an edit request already in flight. The turn then
issued the authoritative final edit to the same message ref, so a slower
in-flight partial-text edit could land after it and leave truncated text as the
last write. stop() now awaits any in-flight edit (and makeChannelStreamTap's
flush/cancel and the turn finally await stop()), so the final edit is always the
last write.
Eric Allam
693c646424