Function hash_set 

pub fn hash_set<S: IntoIterator, H: Hasher>(set: S, hasher: &mut H)
where
    S::Item: Hash,

Hashes a set of items, independently of their iteration order.

The standard library does not (yet) provide a Hash implementation for set types. This can be used instead.

Note that this function is not particularly strong and does not protect against DoS attacks.