Rendered hook / serverPrefetch Vue3 SSR

Question

I've been trying to make a Vue3 app work with SSR and I'm stuck in the serverPrefetch part. I want to load some data in the server, save it in the store and pass it to the client but it looks like the rendered hook referred to here: https://ssr.vuejs.org/guide/data.html#final-state-injection is not called anymore (and therefore the server store is not updated after the data fetch). Do you know what the right way to do this with Vue3 is?

This is my server-entry.js

import { _createApp } from "./app";

export default async (context) => {
  const { app, router, store } = _createApp();

  router.push(context.url); // push router entry

  await router.isReady();

  context.rendered = () => {
    // this is never executed!!!
    context.state = store.state; // this gets embedded in the final HTML as window.__INITAL_STATE__
  };
  return app;
};