AsHashTree - what is it? Does it require data to be hashed?

[vporton]

From https://docs.rs/ic-certified-map/latest/ic_certified_map/trait.AsHashTree.html it's unclear the following:

For AsHashTree is it required that leafs are pseudorandom?

If I, for example, have an u64 value, transform is to U256 and further to [u8; 32] and then to Vec<u8> of length 32, will it be a suitable value for a leaf? It isn't a pseudo-random hash, because it has leading zeros.

[adamspofford-dfinity]

There's no requirement that it be opaque. The leaves can be the data, or a hash of the data, or anything else. As long as the meaning of the data is unambiguous because the branch name is meaningful. The value of the leaf will be hashed alongside a leaf marker when the root hash is constructed.