Apparently, Windows does have precisely that, Flush­File­Buffers [0][1]. The analogue in the Unix world is fsync(). Of course, some hard drives lie about actually having written their caches down, in which case there is nothing much anyone can do.

[0] https://learn.microsoft.com/en-us/windows/win32/api/fileapi/...

[1] https://devblogs.microsoft.com/oldnewthing/20170510-00/?p=95...