Migrating from Declarative to Programmatic additionalResolver

[cancan101]

Reposting from my comment here: #3115 (comment) and due to the limitations of the declarative additionalResolver from here #3115 (comment), I am trying to write a programmatic additionalResolver which makes an API call. However in order to call the API i need to pass on a selectionSet based on the input and potentially nesting it (ie if a connection). There is a function, generateSelectionSetFactory that does this for the Declarative additionalResolver but nothing like that is exposed that I could find.

Is there a function that I could use rather than re-implementing the logic in generateSelectionSetFactory?