Respond with 404 and a single space to `/favicon.ico` requests

router/router.go

@@ -108,7 +108,10 @@ func (r *Router) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
 
 		if req.URL.Path == r.faviconRoute {
 			// TODO: Add a real favicon maybe?
-			rw.WriteHeader(200)
+			rw.Header().Set("Content-Type", "text/plain")
+			rw.WriteHeader(404)
+			// Write a single byte to make AWS Lambda happy
+			rw.Write([]byte{' '})
 			return
 		}
 	}