How to create timer in Lua Server Runtime

I am new at Nakama and I wnat to use the server rumtime to creat the traffic light system, by putting the countdown timer and send the colour status to the game client. But I need to add the countdown finction, how to do that? It seems that I cannot use timer.performWithDelay and sleep etc?

Thanks!

You shouldn’t use Timers. Instead you should use an AuthoritativeMatch that sends the traffic light colours as per GameLoop invocation to your client(s).