Replace FieldGetter/Datum dispatch with typed column writers #432
Description
Search before asking
- I searched in the issues and found nothing similar.
Description
The current write path goes through double enum dispatch (FieldGetter → Datum) and runtime downcasts (as_any_mut().downcast_mut::()) per value.
Typed column writers (like Java's ArrowFieldWriter subclasses) would write directly to concrete builders, closing the ~2.5x throughput gap vs raw Arrow.
Willingness to contribute
- I'm willing to submit a PR!