Early hints not working in Chrome 109

[Alex Hamer]

Hi

Locally I am trying to setup an application to trial early hints.

The app is a basic node application running on https://localhost:80 using node version 18.12.0 running as a http2 server, and utilising nodes "writeEarlyHints" method.

Curling this url I can see the 103 status code and response being generated correctly ('</styles.css>; rel=preload; as=style') and if I change the response to reference a resource that is not used on the page I can see a warning in chrome.

"The resource https://localhost:80/styles1.css was preloaded using link preload in Early Hints but not used within a few seconds from the window's load event."

However when I review whats happening in the chrome dev tools when loading the page (SSR), the initiator for the resource is not "early hints" and the network waterfall is unaffected (even when I artificially slow down the page significantly)

I'm running 108.0.5359.124 (Official Build) (x86_64).

I have tried running chrome  --enable-features=EarlyHintsPreloadForNavigation (is the default for this feature disabled?) but cannot get early hints being respected.

Any hints or tips to resolve this?

Thanks in advance