Function concordium_std::serial_hashset_no_length

pub fn serial_hashset_no_length<W, K>(
    map: &HashSet<K, BuildHasherDefault<FnvHasher>, Global>,
    out: &mut W
) -> Result<(), <W as Write>::Err>where
    W: Write,
    K: Serial,

Write a HashSet as a list of keys in no particular order, without the length information.