Function borrow_decode 

pub fn borrow_decode<'de, Context, D, T, S>(
    decoder: &mut D,
) -> Result<RingSet<T, S>, DecodeError>
where
    D: BorrowDecoder<'de, Context = Context>,
    T: BorrowDecode<'de, Context> + Eq + Hash,
    S: BuildHasher + Default,