Benchmark: running regex, split, each for at least 50 CPU seconds...
     regex: 68 wallclock secs (54.11 usr +  0.13 sys = 54.24 CPU) @ 40957.93/s (n=2221558)
     split: 56 wallclock secs (49.95 usr +  0.05 sys = 50.00 CPU) @ 38128.48/s (n=1906424)