code: public ZipFileBuilder asZip() {
          final ZipFileBuilder zfb = new ZipFileBuilder(folder, filename);
          if(this.content != null) {
              zfb.addResource(getContenFileName(), this.content);
          }
          return zfb;
      }
docs: Indicates the content for the file should be zipped. If only one content reference is provided, the zip
  will only contain this file.
  @return
  the builder