merging 'extensions' field of responses in schema stitching

[nick-stephen]

We're using graphql stitching with remote executors, and would like to be able to merge / pass through the 'extensions' field from the responses in the sub-schemas. Responses contain 'data' and 'errors' but also optionally an 'extensions' field. Currently the extensions information is being lost.

I couldn't see any examples or interface where we may be able to merge this field from the sub-graph responses. Any help welcome!

Thanks!