Method layout

cpp/src/arrow/type.h:562–565

  int bit_width() const override { return static_cast<int>(sizeof(C_TYPE) * CHAR_BIT); }

  DataTypeLayout layout() const override {
    return DataTypeLayout(
        {DataTypeLayout::Bitmap(), DataTypeLayout::FixedWidth(sizeof(C_TYPE))});
  }

  std::string name() const override { return DERIVED::type_name(); }