public ExcelWriterBuilder inMemory(Boolean inMemory) {
        writeWorkbook.setInMemory(inMemory);
        return this;
    }
Write excel in memory. Default false, the cache file is created and finally written to excel.
<p>
Comment and RichTextString are only supported in memory mode.
fastexcel-core/src/main/java/cn/idev/excel/write/builder/ExcelWriterBuilder.java