code: func (net *Network) DidConnect(one, other enode.ID) error {
  	net.lock.Lock()
  	defer net.lock.Unlock()
  	conn, err := net.getOrCreateConn(one, other)
  	if err != nil {
  		return fmt.Errorf("connection between %v and %v does not exist", one, other)
  	}
  	if conn.Up {
  		return fmt.Errorf("%v and %v already connected", one, other)
  	}
  	conn.Up = true
  	net.events.Send(NewEvent(conn))
  	return nil
  }
docs: // DidConnect tracks the fact that the "one" node connected to the "other" node