pub trait Write {
    // ...

    fn write_all_vectored(&mut self, mut bufs: &mut [IoSlice<'_>]) -> io::Result<()> {
        while !bufs.is_empty() {
            match self.write_vectored(bufs) {
                Ok(0) => {
                    return Err(Error::new(
                        ErrorKind::WriteZero,
                        "failed to write whole buffer",
                    ));
                }
                Ok(n) => bufs = IoSlice::advance(mem::replace(&mut bufs, &mut []), n),
                Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
                Err(e) => return Err(e),
            }
        }
        Ok(())
    }
}