Thanks for that! zsv looks amazing. Yeah, it's definitely going to whip GoAWK, what with SIMD parsing and careful memory handling. I've done a couple of basic things for GoAWK's CSV performance, but haven't profiled or looked at allocation bottlenecks (absolute performance definitely wasn't my first focus).
Yeah, sorry about huge.csv -- I found it online somewhere originally by searching for something like "large csv example", but can't for the life of me find it now. It's a monster 1.5GB file with 286 columns including quoted fields (whereas worldcitiespop only has a few columns and it doesn't look like it has quoted fields). I can upload to a file transfer service and send a link to you if you want ... though I should really update my benchmarks to use an easily-downloadable file instead.