Count Down timer utility

TimerUtility.kt

import android.os.CountDownTimer

class CountdownTimerUtility {
    var countdowntimer: CountDownTimer? = null

    //start timer function
    fun startTimer(duration: Long, countDownStep: Long, executeOnFinish: ()->Unit) {
        countdowntimer = object : CountDownTimer(duration, countDownStep) {
            override fun onTick(millisUntilFinished: Long) {}

            override fun onFinish() {
                executeOnFinish()
            }
        }
        countdowntimer!!.start()
    }

    fun cancelTimer() {
        if (countdowntimer != null)
            countdowntimer!!.cancel();
    }
}