Function ostree::diff_dirs

pub fn diff_dirs<P: IsA<File>, Q: IsA<File>, R: IsA<Cancellable>>(
    flags: DiffFlags, 
    a: &P, 
    b: &Q, 
    modified: &[&DiffItem], 
    removed: &[File], 
    added: &[File], 
    cancellable: Option<&R>
) -> Result<(), Error>