Implement Hash for collections about hashbrown HOT 2 CLOSED

Actually, you can use a commutative operator to put together the hash of the hashmap given the hashes of the keys and values. I know that other languages do this, so it's definitely not impossible.
Would you like me to give an example implementation?
rust-lang/rust#21182 (comment)
For those not concerned with DDoS attacks with our hashmaps and hashsets, security concerns aren't an issue at all. Of course, mixing for hashmaps will be a bit problematic as you have to choose to hash or not hash the values.

from hashbrown.

Unfortunately this is not possible because the ordering of the elements in a HashMap is non-deterministic but the hash value depends on the ordering. This means that two HashMaps with the same contents may have different hashes because the elements are in a different order internally.

from hashbrown.