Benchmark: running index, regex for at least 5 CPU seconds...
     index:  6 wallclock secs ( 6.56 usr + -0.03 sys =  6.53 CPU) @ 8119742.77/s
 (n=53030040)
     regex:  5 wallclock secs ( 5.50 usr +  0.00 sys =  5.50 CPU) @ 4481230.91/s
 (n=24646770)
           Rate regex index
regex 4481231/s    --  -45%
index 8119743/s   81%    --