I spun the JSON decoding off into a few goroutines and managed to get it down to ~1second (but it was out of order, so didn't quite solve the same problem - tho

I spun the JSON decoding off into a few goroutines and managed to get it down to ~1second (but it was out of order, so didn't quite solve the same problem - though this is fixable). This is was ~10 lines of Go (and only using a single core).