Yeah really doesn't add up - 2 ms to just return a code? What could it possibly be doing with so much time.
The 2ms delay would be just about right.
I think Netty tries too hard to be everything to everyone. This makes it really hard to determine how to configure it properly across a bunch of different versions with lots of incompatibilities.
I wrote java-http with the concept of not doing that. It's purpose built for HTTP and high performance.
Once I have some time, I'll publish my Netty setup and let the community bang on it and see if they can beat my RPS. At 65k, it might be hard though. :)
[0] https://github.com/zio/zio-http