Function mz_transform::reduction_pushdown::try_push_reduce_through_join

fn try_push_reduce_through_join(
    inputs: &Vec<MirRelationExpr>,
    equivalences: &Vec<Vec<MirScalarExpr>>,
    group_key: &Vec<MirScalarExpr>,
    aggregates: &Vec<AggregateExpr>,
    monotonic: bool,
    expected_group_size: Option<u64>
) -> Option<MirRelationExpr>