如何测试给定的函数代码单元(c#)是否没有创建或写入任何文件到磁盘?

Imagine there's a mission-critical process that'll be used in a business which handles sensitive information (think of Credit Card, social security, patient records...etc). I would think this unit ideally should do whatever it has to do on-the-fly, meaning it won't intentionally write files to disk containing sensitive information. The idea here is that if the computer that runs this process is compromised, no sensitive information can be leaked, at least not by means of files.Imagine there's a mission-critical process that