code: function(terria, url) {
    DataSourceCatalogItem.call(this, terria);
  
    this._dataSource = undefined;
  
    this.url = url;
  
    /**
     * Gets or sets the CZML data, represented as a binary Blob, JSON object or array literal, or a Promise for one of those things.
     * If this property is set, {@link CatalogItem#url} is ignored.
     * This property is observable.
     * @type {Blob|Object|Promise|Array}
     */
    this.data = undefined;
  
    /**
     * Gets or sets the URL from which the {@link CzmlCatalogItem#data} was obtained.  This will be used
     * to resolve any resources linked in the CZML file, if any.
     * @type {String}
     */
    this.dataSourceUrl = undefined;
  
    knockout.track(this, ["data", "dataSourceUrl"]);
  }
docs: A {@link CatalogItem} representing Cesium Language (CZML) data.
  
  @alias CzmlCatalogItem
  @constructor
  @extends CatalogItem
  
  @param {Terria} terria The Terria instance.
  @param {String} [url] The URL from which to retrieve the CZML data.