GH-37635: [Format][C++][Go] Add app_metadata to FlightInfo and FlightEndpoint

[zeroshade]

Rationale for this change

As suggested here: #37635 (comment) this just adds an app_metadata field to FlightInfo and FlightEndpoint

What changes are included in this PR?

Just the updated proto file and the generated Go code from the proto

Are there any user-facing changes?

Yes.

This PR includes breaking changes to public APIs.

• Closes: [FlightRPC] FlightSQL: Expose custom query metadata #37635

[github-actions]

⚠️ GitHub issue #37635 has been automatically assigned in GitHub to PR creator.

[lidavidm]

Could we also add unit/integration tests?

[zeroshade]

@lidavidm currently in the process of doing so

[kou]

Vote thread: https://lists.apache.org/thread/113xm107ptn1t76txockp11oc7wlh0ok

[lidavidm]

I think we generally require integration tests as well?

[zeroshade]

I'll set up integration tests for this sometime this week!

[lidavidm]

Can you rebase? It appears integration tests didn't run

[zeroshade]

rebased!

[kou]

+1

[kou]

I'll merge #37867 and rebase this to fix CI failures.

[zeroshade]

Thanks @kou! Hopefully we can get one more vote on the ML so that we can close the vote and merge this. I'll see if i can poke some people

[pitrou]

To be clear, there's no requirement that the app_metadata in a FlightData is the same as the app_metadata for the FlightInfo or FlightEndpoint which led to that data?

[zeroshade]

@pitrou correct there's no requirement for it, the integration test is just using that to validate the values are as expected

[conbench-apache-arrow]

After merging your PR, Conbench analyzed the 5 benchmarking runs that have been run so far on merge-commit 92de9a3.

There were no benchmark performance regressions. 🎉

The full Conbench report has more details. It also includes information about 5 possible false positives for unstable benchmarks that are known to sometimes produce them.