Scanner needs to scan files being deleted to catch certain kinds of malware, and Windows blocks until it's actually scanned and deleted. Lots of file operation

Scanner needs to scan files being deleted to catch certain kinds of malware, and Windows blocks until it's actually scanned and deleted. Lots of file operations are like this on Windows. It makes filesystem operations seemingly easier to program/understand, but much much slower. I suspect the synchronisation assumptions it is allowing are also deeply ingrained in legacy code. Any serious Windows app needs to spawn many threads to work around this performance issue when batch operating on lots of files.