Function add_file_to_tar_from_walk 

fn add_file_to_tar_from_walk<W: Write>(
    tar_builder: &mut Builder<W>,
    dir: &Dir,
    filename: &OsStr,
    absolute_path: &Path,
    relative_path: &Path,
    sepolicy: Option<&SePolicy>,
    hardlinks: &mut HashMap<(u64, u64), PathBuf>,
) -> Result<()>