[john_kerl]

The 10x number was before improvements on https://github.com/johnkerl/miller/pull/786 et al. The earlier negative perf results were my fault, not Go's -- I was focusing initially on the port and feature development, leaving benchmarking and optimization until the end. That said, Go is a bit slower than C line for line; however, Miller 5 (in C) was single-threaded and Miller 6 (in Go) actively uses multicore. This is why complex processing chains now run much quicker in Go than in C -- due to multicore and pipelining which are much easier to do in Go.