Function zip_dir 

pub fn zip_dir<T>(
    it: &mut dyn Iterator<Item = DirEntry>,
    prefix: &str,
    writer: T,
) -> ZipResult<()>
where
    T: Write + Seek,

压缩指定路径的所有文件到zip ###Example:

 use rcmd_core::util::filesys::zip_dir;
 use rcmd_core::Ex::walkdir::WalkDir;

 let zipfile = std::fs::File::create(target).unwrap();
 let dir  = WalkDir::new(src_dir);
 zip_dir(&mut dir.into_iter().filter_map(|e|e.ok()), src_dir.to_str().unwrap(), zipfile);