pub fn parallel_count_default<T, F>(input: &[T], counter: F) -> u64where T: Send + Sync + Clone + 'static, F: Fn(&[T]) -> u64 + Send + Sync + 'static,
Phase 3.4 wiring entry point for COUNT(*) over a filtered scan. Same default parallelism as parallel_scan_default.
parallel_scan_default