test/e2e/resources/network/eventstream.html - devtools/devtools-frontend - Git at Google

 <!DOCTYPE html>
 <body>
   <script>
     const url = 'event-stream.rawresponse'
     const evtSource = new EventSource(url);
     window.addEventListener('beforeunload', () => {
       evtSource.close()
     });
   </script>
 </body>
	<!DOCTYPE html>
	<body>
	<script>
	const url = 'event-stream.rawresponse'
	const evtSource = new EventSource(url);
	window.addEventListener('beforeunload', () => {
	evtSource.close()
	});
	</script>
	</body>