Method set_use_threads

cpp/src/parquet/arrow/reader.cc:364–366

  int num_row_groups() const override { return reader_->metadata()->num_row_groups(); }

  void set_use_threads(bool use_threads) override {
    reader_properties_.set_use_threads(use_threads);
  }

  void set_batch_size(int64_t batch_size) override {
    reader_properties_.set_batch_size(batch_size);