If the e-mail application had made sure that those messages were promptly written to the local disk, even before it informed the server that the messages were successfully downloaded, the problem would never have arisen.

• 如果邮件程序先确保那些邮件写到了本地磁盘，然后通知服务器那些邮件已经成功地下载，就不会出现这种问题。