anchor.diff:      })
     );
   }
  +
  +function skipWaiting() {
  +  if (self.skipWaiting != undefined) {
  +    self.skipWaiting();
  +  }
  +}
   ''';
   }
  
positive.code:   // SkipWaiting can be used to immediately activate a waiting service worker.
    // This will also require a page refresh triggered by the main worker.
    if (event.data === 'skipWaiting') {
      return self.skipWaiting();
    }
    if (event.message === 'downloadOffline') {
      downloadOffline();
    }
  });
  
  
negative.code:   ${coreBundle.map((String file) => '"$file"').join(',\n')}];
  // During install, the TEMP cache is populated with the application shell files.
  self.addEventListener("install", (event) => {
    skipWaiting();
    return event.waitUntil(
      caches.open(TEMP).then((cache) => {
        return cache.addAll(
  