discussion: ConnectionGetObjects vs ConnectionGetTableSchema

### What would you like help with?

ConnectionGetObjects is more general and more flexible but it doesn't return Arrow-specific type information. Having to call both of these APIs in the client might result in two round-trips to a server, which would be unfortunate. What if we were to do something like add a new column TABLE_SCHEMA.column_schema which contains a serialized Arrow schema? It would be null if the depth didn't include column information, of course.

Or am I missing something?