code: function Asset(filePath, urlPath, fileType, cacheable, hash, sourceMapUrlPath, size, bundle) {
      this.filePath = filePath;
      this.urlPath = urlPath;
      this.fileType = fileType;
      this.cacheable = cacheable;
      this.hash = hash;
      this.entrySize = size;
      this.sourceMapUrlPath = sourceMapUrlPath;
      this.bundle = bundle;
  
      this.getFile = function getFile() {
          return path.join(this.bundle.directoryUri, filePath);
      };
  }
docs: Represent single asset in the bundle.
  
  @property {string} filePath
  @property {string} urlPath
  @property {string} fileType
  @property {number} size
  @property {bool}   cacheable
  @property {string} hash
  @property {string} sourceMapFilePath
  @property {string} sourceMapUrlPath
  @property {AssetBundle} bundle
  @constructor