Intermittent connection refused error in TestSDKRPCServerBackend about yorkie HOT 2 CLOSED

func (s *Server) listenAndServe() error {
	go func() {
		time.Sleep(5 * time.Second)
		logging.DefaultLogger().Infof(fmt.Sprintf("serving RPC on %d", s.conf.Port))
...

// WaitForServerToStart waits for the server to start.
func WaitForServerToStart(addr string) error {
	maxRetries := 10
	initialDelay := 100 * gotime.Millisecond
	maxDelay := 5 * gotime.Second

	for attempt := 0; attempt < maxRetries; attempt++ {
		// Exponential backoff calculation
		delay := initialDelay * gotime.Duration(1<<uint(attempt))
		fmt.Println("delay: ", delay)
		if delay > maxDelay {
			delay = maxDelay
		}

		conn, err := net.DialTimeout("tcp", addr, 1*gotime.Second)
		if err != nil {
			gotime.Sleep(delay)
			continue
		}

		err = conn.Close()
		if err != nil {
			return err
		}

		return nil
	}

	return fmt.Errorf("failed to connect server via %s", addr)
}