zlib-rs is used at run time in 60 crates (of which 22 optionally). It is a direct run-time dependency in 5 crates. It's used only as a dev dependency in 3 crates.

Depender (with downloads and own rev deps) zlib-rs version
18.3M 1054 rustls optional ^0.4
71K 2 libz-rs-sys ^0.4.2
170 portable-rustls optional ^0.4
110 supply-chain-trust-example-crate-000092 optional ^0.4
1 compu optional ^0.4.1