docs: @Override
      public final CacheKey getCacheKey(HttpServletRequest request, HttpServletResponse response) {
          final Resource stylesheetResource = this.getStylesheetResource(request);
          final Serializable stylesheetCacheKey;
          try {
              stylesheetCacheKey = this.xmlUtilities.getStylesheetCacheKey(stylesheetResource);
          } catch (TransformerConfigurationException e) {
              throw new RuntimeException(
                      "Failed to get Transformer for stylesheet: " + stylesheetResource, e);
          } catch (IOException e) {
              throw new RuntimeException("Failed to load stylesheet: " + stylesheetResource, e);
          }
  
          return CacheKey.build(stylesheetResource.getDescription(), stylesheetCacheKey);
      }