No error messages shown when preloading from a non-existent route in layout-component

[arggh]

When trying to...

1. preload from a layout component...
2. with code copy-pasted from the documentation...
3. but you have a typo in the route URL or you otherwise manage to fetch from a non-existent endpoint...
4. ➜ the browser keeps loading forever, displaying a blank page and prints Uncaught (in promise) TypeError: Failed to fetch in the console.

The server console doesn't tell me anything went wrong.

Reproduction

https://github.com/arggh/svelte-preload-issue

How to improve

• Maybe stop loading the page and show a similar error message as when the preloading fails in a page component?

• Maybe show an error message in the server's console?

Might be related?

Should we not preload from the layout-component in the first place? #275