Suggestion: Add option `same_file_system` like walkdir has

[Boscop]

Thanks for this crate, it's really faster than walkdir. I'm just missing this option, could you please add it? :) https://docs.rs/walkdir/2.3.1/walkdir/struct.WalkDir.html#method.same_file_system https://github.com/BurntSushi/walkdir/pull/110

[jessegrosjean]

I don't have need for it now, but I will accept pull request.