lz4-sys is used at run time in 114 crates (of which 22 optionally, 4 directly). It's used only as a dev dependency in 7 crates.

Depender (with downloads and own rev deps) lz4-sys version
57K 53 lz4 ^1.9.2
40K 3 rdkafka-sys optional ^1.8.3
300 2 clickhouse optional ^1.9.2
arq ^1.9