Function mutable_var_length_rows

cpp/src/arrow/compute/row/row_internal.h:237–240

    return data(2);
  }
  uint8_t* mutable_var_length_rows() {
    ARROW_DCHECK(!metadata_.is_fixed_length);
    return mutable_data(2);
  }

  /// \brief True if there is a null value anywhere in the table
  ///