pub async fn try_route_preload(&self, url: &str) -> Result<(), ClientError> {
        self._preload(url, true).await
    }
A version of `.route_preload()` that returns a future that can resolve
to an error. If the path you're preloading is not hardcoded, you
should use this. Localization will be
handled automatically.

To preload a widget, you must prefix its path with `__capsule/`.
packages/perseus/src/reactor/state.rs