test: improve flaky http2-stream-destroy-event-order

test/parallel/test-http2-stream-destroy-event-order.js

@@ -23,7 +23,16 @@ server.listen(0, common.mustCall(() => {
   req.resume();
   req.on('error', common.mustCall(() => {
     req.on('close', common.mustCall(() => {
-      client.close();
+      // TODO(lundibundi): fix flakiness of this use case, the setTimeout must
+      // not be needed here. Specifically if the settings frame on the client
+      // is 'delayed' and only comes after we have already called
+      // `req.close(2)` then the 'close' event will be emitted before the
+      // stream has got a chance to write the rst to the underlying socket
+      // (even though FlushRstStream and SendPendingData have been called) and
+      // since we are destroying a session here it will never be written
+      // resulting in a 'clean' stream close on the server side and therefore a
+      // timeout because there will be no error.
+      setTimeout(() => client.close(), 0);
     }));
   }));
 }));