[Feature request] Subscriptions with dynamic (federated) schema support

[tot-ra]

Would be nice to have a possibility of gqlgen to act as subscription server with dynamic schema. Right now I can use gqlgen as a basic subscription server, but if I want to enrich subscriptions with data from federated gateway, I don't see a way to do it.

So what we need is

• Loading dynamic federated schema (from the gateway & merging with subscriptions), or from schema-registry
• Generic resolver function that would take into properties and make requests against the gateway to get enriched result

See:
https://youtu.be/C5pSwLpjZM0
https://github.com/apollosolutions/federation-subscription-tools