ch_cityhash102 is a native no_std Rust implementation of ClickHouse's
CityHash version. ClickHouse uses specific old version of the
CityHash algorithm (1.0.2, as per
ClickHouse/ClickHouse#8354).
Two versions are implemented: cityhash64 used in ClickHouse's query
language, and cityhash128 used in the ClickHouse protocol.