HMAC-based Extract-and-Expand Key Derivation Function (HKDF). U can watch rust implemntation and took tests from [there](https://github.com/rust-bitcoin/rust-bitcoin/blob/0123f2894c66419f1ad561e9e7d98af66c4db9ab/hashes/src/hkdf.rs). Hmac already implemented in zig [std](https://ziglang.org/documentation/master/std/#std.crypto.auth.hmac)
HMAC-based Extract-and-Expand Key Derivation Function (HKDF).
U can watch rust implemntation and took tests from there.
Hmac already implemented in zig std