chore(arrow-flight-sql): remove register_sql_info from FlightSqlService

[mnpw]

Which issue does this PR close?

N/A

Rationale for this change

FlightSqlService::register_sql_info appears to be stale artefact and it is effectively a no-op in the trait definition. It appears to be carried over from Go's BaseServer implementation.

Since FlightSqlService intends to represent Go's Server implementation instead it makes sense to remove this method from FlightSqlService.

Note: An alternative to removal of this method is change in its signature to FlightSqlService::register_sql_info(id: SqlInfo, result: SqlInfoValue). I can implement that instead as well but it deviates from what FlightSqlService trait should be doing.

What changes are included in this PR?

Remove register_sql_info from FlightSqlService

Are these changes tested?

Tested via -

cargo test -p arrow-flight --all-features

Are there any user-facing changes?

Yes. This removes a public trait method. Implementors that currently define register_sql_info as part of their FlightSqlService implementation must remove it.

[Rich-T-kid]

What are the downsides to keeping it? Since this is would be a breaking API change we'd need to depreciate it first.

• https://github.com/apache/arrow-rs#release-versioning-and-schedule
• #5368