private UniqueDataFlagKey uniqueDataFlag(WriteSheetHolder writeSheetHolder, String wrapperName) {
        return new UniqueDataFlagKey(writeSheetHolder.getSheetNo(), writeSheetHolder.getSheetName(), wrapperName);
    }
To prepare data

@param cell          cell
@param rowIndex      row index
@param columnIndex   column index
@param firstRowCache first row cache
@return Returns the data that the cell needs to replace
fastexcel-core/src/main/java/cn/idev/excel/write/executor/ExcelWriteFillExecutor.java