public ExcelReaderBuilder extraRead(CellExtraTypeEnum extraType) {
        if (readWorkbook.getExtraReadSet() == null) {
            readWorkbook.setExtraReadSet(new HashSet<CellExtraTypeEnum>());
        }
        readWorkbook.getExtraReadSet().add(extraType);
        return this;
    }
Read some extra information, not by default

@param extraType extra information type
@return
fastexcel-core/src/main/java/cn/idev/excel/read/builder/ExcelReaderBuilder.java