perl-5.28.1 (Windows 10 Pro)
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             Rate      regex      index filehandle      split
regex      8.09/s         --       -14%       -17%       -33%
index      9.46/s        17%         --        -3%       -22%
filehandle 9.73/s        20%         3%         --       -20%
split      12.2/s        50%        29%        25%         --