code: function (config) {
              var url = config.url,
                  viewerAPI = scope.getConfig().api;
  
              if (url) {
                  viewerAPI.download = function () {
                      download(url);
                  };
              }
          }
docs: Initialize the download plugin
  @param   {Object} config     The config object
  @param   {string} config.url The download URL
  @returns {void}