Benchmark: running use_qr, use_re, use_str for at least 5 CPU seconds...
    use_qr:  5 wallclock secs ( 5.23 usr +  0.00 sys =  5.23 CPU) @ 98736.51/s (n=515997)
    use_re:  5 wallclock secs ( 5.33 usr +  0.00 sys =  5.33 CPU) @ 23.99/s (n=128)
   use_str:  5 wallclock secs ( 5.23 usr +  0.00 sys =  5.23 CPU) @ 2268.47/s (n=11855)
           Rate  use_re use_str  use_qr
use_re   24.0/s      --    -99%   -100%
use_str  2268/s   9355%      --    -98%
use_qr  98737/s 411431%   4253%      --