How do I create a NSTimer on a background thread?

Question

I have a task that needs to be performed every 1 second. Currently I have an NSTimer firing repeatedly every 1 sec. How do I have the timer fire in a background thread (no

Answer 1

class BgLoop:Operation{
    func main(){
        while (!isCancelled) {
            sample();
            Thread.sleep(forTimeInterval: 1);
        }
    }
}