Can I return promises with the new data() helper

[rjmackay]

I've enabled single fetch in my app and I'm trying to remove one of the defers. Currently it looks like

return defer({
       someData: { ... },
       someDeferredPromise: fetchAsync()
    },
    {
      headers: {
        // clear session flash
        'Set-Cookie': await commitSession(session),
      },
    }
)

If I swap the defer() for the data() helper and then call useLoaderData(). I'm not getting empty objects for all the promises, even after they're pass through <Await />. Is that expected? Does anyone have a working example using data() and deferring some of the data loading?