The wait ensures that cluster goes into the stable stage, which means that
leader has been elected and starts to heartbeat to followers.
This makes future client requests always handled in time, and there is no
need to retry sending requests.
It is the correct thing to do to ensure that the communication is full
of out-of-date messages.
It results in that integration testing is very easy to throw MsgProp away,
and makes client wait until 5 min timeout. Sync interval and heartbeat are
increased to alleviate the traffic.
Removes the notion of name being anything more than advisory or
command-line grouping, and adds checks for bootstrapping the command
line. IDs are consistent if the URLs are consistent.
