mutagen
impl<R> Read for Box<R> where R: Read + ?Sized, impl<W> Write for Box<W> where W: Write + ?Sized, impl<I> Iterator for Box<I> where I: Iterator + ?Sized, type Item = <I as Iterator>::Item;
pub fn forloop<'a, I: Iterator + 'a>( i: I, n: usize, flag: &AtomicUsize, mask: usize) -> Box<Iterator<Item = I::Item> + 'a>