Removed http/2 push for service worker prefetches

sw/service-worker.ts

@@ -211,8 +211,14 @@ class MyServiceWorker {
 	prefetchFullPage(url: string) {
 		let fullPage = new Request(url.replace("/_/", "/"))
 
+		// Disable HTTP/2 push responses
+		let headers = new Headers({
+			"X-Source": "service-worker"
+		})
+
 		let fullPageRefresh = fetch(fullPage, {
-			credentials: "same-origin"
+			credentials: "same-origin",
+			headers
 		}).then(response => {
 			// Save the new version of the resource in the cache
 			let cacheRefresh = caches.open(this.cache.version).then(cache => {