Schema Extensions: How to transform result to returnType using a resolver?

[greenGizmo]

Hi, I am trying to extend my schema using the @resolveTo directive. It works so far, that the underlying source is called with the correct params and I get the expected result. The problem is, that the response I get is not the same type as the type that should be returned. So I have to run a mapper or transformer between these two types. The documentation mentions that this is possible using a resolver:

https://the-guild.dev/graphql/mesh/v1/schema-extensions#basic-example

By default, resolveTo assumes that the delegated operation will return the same GraphQL type as the resolved field (ex: a User field would delegate to a User query). If this is not the case, then you should manually provide a returnType option citing the expected GraphQL return type, and transform the result accordingly in the resolver.

What is missing is how to implement that resolver. I already tried to implement additionalResolvers in my gateway (hive), but as soon as I use @resolveTo in my schema these are ignored and not called anymore.

I think there should be an example or a page dedicated to @resolveTo to explain such scenarios. In v0 it was possible to reference a resolver for the extend transform (https://the-guild.dev/graphql/mesh/docs/transforms/extend) which is now missing.