`graphql-kafka` feature

[jfallows]

GraphQL (Octorber 2021) specification

• [ ] Implement codec support for graphql server; query, subscription, mutation
• [ ] Map query to type-filtered kafka fetch, returning all fields, completing response after catching up to live messages
• [ ] Map subscription to type-filtered kafka fetch, returning all fields
• [ ] Map mutation to kafka produce with ack mode
• [ ] Use typed sub-schema support to convey dynamic subset of selected fields for query and subscription
• [ ] Provide example via graphql over ws in zilla-examples
• [ ] Consider sse-graphql mapping to transform sse query params into graphql subscription fields

TODO: capture progress for reliable subscription message delivery and replay observed progress on subscription recovery, similar to query pagination cursor.

[dudo]

It'd be clutch if this could comply with Apollo's subgraph functionality.

https://www.apollographql.com/docs/federation/building-supergraphs/supported-subgraphs/