Verify windows implementation

[nicokoch]

Is only compile-tested at the moment

As a head's up, FSCTL_DUPLICATE_EXTENTS_TO_FILE only works on ReFS which is only available on Windows Server 2016+. To makes things worse, ReFS volumes are not bootable. Therefore, this will not work on any Windows boot volume.

Running the example on 99.999% of Windows volumes will result in this:
thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: Os { code: 1, kind: Other, message: "Incorrect function." }', libcore\result.rs:945:5

Sorry to be the bearer of bad news!

[nicokoch]

Running the example on 99.999% of Windows volumes will result in this:
thread 'main' panicked at 'called Result::unwrap() on an Err value: Os { code: 1, kind: Other, message: "Incorrect function." }', libcore\result.rs:945:5

This is known and expected.
If certain file systems do not support the functionality, we can't to anything about it.

Maybe in the future, some Windows client versions will be supported.