pub fn register_no_state(&self, url: &PathMaybeWithLocale, is_widget: bool) {
        self.state_store.set_state_never(url, is_widget);
    }
Registers a page/widget as definitely taking no state, which allows it
to be cached fully, preventing unnecessary network requests. Any
future attempt to set state will lead to errors (with exceptions for
HSR).
packages/perseus/src/reactor/state.rs