Document support (or lack of) for netty-tcnative

This is an enhancement request regarding documentation. It started as a comment on https://github.com/spring-cloud/spring-cloud-gateway/issues/301 ut was not 100% related to the use-case discussed.

Please add the following to the documentation for sping-cloud-gateway:

Is it possible to use netty-tcnative with the Gateway starter in some way? It is not documented anywhere in the docs and returns zero usable results on Google. I think this needs to be added to the documentation.

"Just use http" - is not a way forward for us and right now the performance of non-native TLS is holding us back from a production deploy.

But maybe it already works as described in https://github.com/reactor/reactor-netty/issues/344 but I see no logs neither confirming or denying the fact.

I did basic benchmarks (using very lowtech ab) and I see no difference by just including the netty-native uber jar.

The issue targets the Spring Cloud Gateway documentation and references reactor/reactor-netty issue 344; start by checking whether netty-tcnative is supported with the Gateway starter and whether that guidance applies. Document the confirmed setup or limitation, including how users can verify whether native TLS is active.