Actually CRC-16 has a
much better distribution than djb2 and other algorithms for this use case.
CRC-16 is a remarkably good algorithm for certain kind of hashing, and has a few very interesting qualities being the reminder of a polynominal division. For instance if you hash two bytes data you are guaranteed to have different hashes for every different pair of bytes without collisions.
CRC-16 performed very well in tests also with the very common case of keys with the same prefix, like object:0, object:1, and so forth.
So CRC-16 is very good for our use case and has the advantage of being simple and fast.