Performance Tracing Extension

[mathroc]

Is your feature request related to a problem? Please describe.

I’d like to be able to get performance feedback from my queries in case I want to identify which resolver is causing slow queries

Describe the solution you'd like

Apollo has defined a response format for a tracing extension that’s already implemented by multiple GraphQL servers and at least by apollo engine and graphql playground

Describe alternatives you've considered

telemetry can be useful too (#423, #713) when it’s complete enough, but requires additional tooling and is not available easily to the API users

Additional context

https://github.com/apollographql/apollo-tracing

[LegNeato]

Would love this behind a feature flag as it is non-standard.