code: function tiler(root, options) {
      this.root = root;
      options = options || {};
      options.packSize = options.packSize || 128;
      if (!options.storageFormat) {
          options.storageFormat = guessStorageFormat(root);
      }
      this.options = options;
  }
docs: Constructor for the tiler-arcgis-bundle
  
  @param {String} root - the root folder of ArcGIS bundle tiles, where the Conf.xml stands.
  @param {Object} options - options passed in.
  @param {integer} options.packSize - packet size.
  @param {String} options.storageFormat - bundle storage format.
  @class