I was a bit surprised that BTreeMap turned out to be more memory-efficient than HashMap; can anyone shed some light on this? One of these days I’ll get around

I was a bit surprised that BTreeMap turned out to be more memory-efficient than HashMap; can anyone shed some light on this? One of these days I’ll get around to turning my Rust set implementation[0] into a full-blown map (it’s already <50% the size of BTreeSet for ints)... [0] https://github.com/senderista/rotated-array-set https://github.com/senderista/rotated-array-set