refactor(server): migrate to fastify (#707)

server/middleware/eventStream.ts

@@ -17,7 +17,6 @@ export default (req: Request, res: Response, next: NextFunction) => {
   // Keep the connection open by sending a message every so often.
   const keepAliveTimeout = setInterval(() => {
     res.write(':keep-alive\n\n');
-    res.flush();
   }, 500);
 
   // cleanup on close