Swift Run the block of Timer without timer in first time

I created a timer and set it to repeat every 30 seconds
the timer waits 30 seconds to run the first time, then another 30 seconds for the second time, I wanted it to run the first time without the 30 seconds, is there any way?

Timer.scheduledTimer(withTimeInterval: 30, repeats: true) { timer in
            if iteration >= 0 {
            runCommands()
            iteration -= 1
            if iteration == 0 {exit(0)}
        }
    }

>Solution :

Just call fire. It does what the name implies.

Timer.scheduledTimer(withTimeInterval: 30, repeats: true) { timer in
    if iteration >= 0 {
        runCommands()
        iteration -= 1
        if iteration == 0 {exit(0)}
    }
}.fire()