[1] Service Workers Nightly (2/16/2017, 11:10:49 AM) <https://w3c.github.io/ServiceWorker/#service-worker-registration-navigationpreloadmanager>
[2] Speed up Service Worker with Navigation Preloads | Web | Google Developers (2/17/2017, 3:09:13 PM) <https://developers.google.com/web/updates/2017/02/navigation-preload>
Google search: Navigation Preloads