Will throttle the execution to once in every `delay` seconds.

Throttle.swift

func throttle<A>(delay:Int, queue:DispatchQueue, action: @escaping ((A)->())) -> (A)->() {
    var lastFireTime = DispatchTime.now()
    let dispatchDelay = DispatchTimeInterval.milliseconds(delay)

    return { state in
        let dispatchTime: DispatchTime = DispatchTime.now() + dispatchDelay
        queue.asyncAfter(deadline: dispatchTime, execute: {
            let when: DispatchTime = lastFireTime + dispatchDelay
            let now = DispatchTime.now()
            if now.rawValue >= when.rawValue {
                lastFireTime = DispatchTime.now()
                action(state)
            }
        })
    }
}

Example:

let throttledPrint: (String) -> () = throttle(delay: 1000, queue: DispatchQueue.main) { text in
    print(text)
}

// ...

throttledPrint("hello")