A candidate that accepted the dial and then said nothing kept its slot
for the session, and ten of those blocked every later batch; a link now
closes after a minute of silence. A parent that flaps its level made us
tell the server four messages per flap; moves are now told at most once
a second, the latest one winning. A parent that reports level zero is
its own root from then on, whatever it said before. The wait for a
searcher's control connection runs from the last message queued for it,
not the first. A successful login is pinned to reset the leaf.