Method Resize

cpp/src/arrow/compute/kernels/hash_aggregate.cc:1567–1573

  }

  Status Resize(int64_t new_num_groups) override {
    auto added_groups = new_num_groups - num_groups_;
    num_groups_ = new_num_groups;
    RETURN_NOT_OK(ones_.Append(added_groups, static_cast<CType>(0)));
    RETURN_NOT_OK(has_one_.Append(added_groups, false));
    return Status::OK();
  }

  Status Consume(const ExecSpan& batch) override {
    auto raw_ones_ = ones_.mutable_data();