Function concordium_std::deserial_set_no_length

pub fn deserial_set_no_length<R, K>(
    source: &mut R, 
    len: usize
) -> Result<BTreeSet<K>, ParseError> where
    R: Read,
    K: Deserial + Ord + Copy, 

Read a BTreeSet as a list of keys, given some length. NB: This ensures there are no duplicates, hence the specialized type. Moreover this will only succeed if keys are listed in order.