In such case, it didn't reconnect, but thought it was connected,
which eventually led to crashes like:

  Traceback (most recent call last):
    ...
    File "neo/admin/handler.py", line 130, in answerClusterState
      self.app.updateMonitorInformation(None, cluster_state=state)
    File "neo/admin/app.py", line 274, in updateMonitorInformation
      self.upstream_admin_conn.send(Packets.NotifyMonitorInformation(kw))
    File "neo/lib/connection.py", line 565, in send
      raise ConnectionClosed
  neo.lib.connection.ConnectionClosed