how to keep track of Lean Tween function?

I want to know the time left to complete the animation as I am using unity asset Lean Tween to scale down my time bar, so when 5 seconds are left till the time run out I want to play sound of closing time. I was able to know when the animation is gonna end LeanTween.scaleX(timebar.gameObject, 1f, time).setOnComplete(this.Gameover) but how I can get time left to complete? I have looked through documentation but didn't find anything useful