I've been using it in Rust, but librdkafka had (has?) a bug that's been fixed in tree that cut the read throughput to about 10MB/s using loopback (edit: cuts throughput to 10MB/s in many settings, which hurts especially in loopback). With that fixed, it seemed pretty pleasant for my use cases (framed bytestreams at line rates, nothing fancy or web-scale).
Edit: crate I was using, and enjoy (which brings in librdkafka): https://github.com/fede1024/rust-rdkafka