docs: function render (currentTime) {
        // Store time scroll started, if not started already:
        if (!startTime) {
          startTime = currentTime;
        }
  
        // Determine time spent scrolling so far:
        elapsedTime = currentTime - startTime;
  
        // Calculate next scroll position:
        next = easing(elapsedTime, start, distance, duration, settings);
  
        // Scroll to it:
        window.scrollTo(0, next);
  
        // Check progress:
        elapsedTime < duration
          ? window.requestAnimationFrame(render)
          : done(start, startTime, distance, settings);
      }