[john_kerl]

Thanks -- my apologies for the sequencing of the dev work. I focused first on the port per se; second on feature-adds; leaving benchmarking, performance analysis, and optimizations (even some real low-hanging fruit) until last. The 10x number was indeed the case pre-optimization ... on https://github.com/johnkerl/miller/pull/786 you can see tabulated results where Miller 6 is now on par with Miller 5, and in some cases is far faster.