I’m quite pleased with how this has turned out.
Given the stability-despite-instability of hashbrown (that the API
surface we’re depending on hasn’t changed since 0.1.1), and the
deliberate altered SemVer guarantees for it, it was very tempting
to leave the hashbrown range open, `version = ">=0.1.1"` or at least
`version = ">=0.1.1, <1"`, but for some reason or other I ended up
deciding not to. I’m still of two minds about it, really.