function () {
      var sizeDelta = 0;
      var averageSpeed = 0;
      each(this.files, function (file) {
        if (!file.paused && !file.error) {
          sizeDelta += file.size - file.sizeUploaded();
          averageSpeed += file.averageSpeed;
        }
      });
      if (sizeDelta && !averageSpeed) {
        return Number.POSITIVE_INFINITY;
      }
      if (!sizeDelta && !averageSpeed) {
        return 0;
      }
      return Math.floor(sizeDelta / averageSpeed);
    }