my $x = pack 'C*', map int rand(256), 1 .. 64*1024;
my $y = pack 'C*', map int rand(256), 1 .. 64*1024;
using_str_bit_ops_and_s($x, $y) eq using_str_bit_xor($x, $y)
  or die "Results are different??";

use Benchmark 'cmpthese';
cmpthese -3, {
  using_str_bit_ops_and_s => sub{ my $r = using_str_bit_ops_and_s($x, $y) },
  using_str_bit_xor=> sub{ my $r = using_str_bit_xor($x, $y) },
};