Offload query parts in Apollo client

Question

I vaguely remember Apollo supporting a directive / mechanism, which enables offloading parts of the query into a subsequent query. I know this can be achieved combining multiple queries, or by simply loading the details separately, but I think this would be an easy way to provide fast previews without a lot of complexity. I was thinking of something like this:

query {
  foo {
    bar
    baz @async
  }
}

And the first response would be in the format of

{
  "foo": {
     "bar": "something",
     "baz": null // Or a predefined value
   }
}

Once it's loaded, the results are passed down to the component to render, while a subsequent request is made with "baz" included:

{
  "foo" {
     "bar": "something",
     "baz": "else" // baz loaded
   }
}

Is there such a thing, or it was dreaming about it?

Edit:

Apparently there's a deferred directive in the making: https://www.apollographql.com/blog/community/backend/introducing-defer-in-apollo-server/ but I couldn't find any up-to-date information about it.