code: private void readBooleanBatch(int rowId, int num, WritableColumnVector column)
        throws IOException {
      if (column.dataType() != DataTypes.BooleanType) {
        throw constructConvertNotSupportedException(descriptor, column);
      }
      defColumn.readBooleans(
          num, column, rowId, maxDefLevel, (VectorizedValuesReader) dataColumn);
    }
docs: For all the read*Batch functions, reads `num` values from this columnReader into column. It
  is guaranteed that num is smaller than the number of values left in the current page.