prelude: |
  str1 = [*"A".."M",*"n".."z",*"0".."9"].join("")
  str10 = str1 * 10
  str100 = str10 * 10
  str1000 = str100 * 10
  nonascii1 = [*"\u{c0}".."\u{cf}",*"\u{f0}".."\u{ff}"].join("")
  nonascii10 = nonascii1 * 10
  nonascii100 = nonascii10 * 10
  nonascii1000 = nonascii100 * 10
benchmark:
  swapcase-1: str1.swapcase
  swapcase-10: str10.swapcase
  swapcase-100: str100.swapcase
  swapcase-1000: str1000.swapcase
  swapcase-nonascii1: nonascii1.swapcase
  swapcase-nonascii10: nonascii10.swapcase
  swapcase-nonascii100: nonascii100.swapcase
  swapcase-nonascii1000: nonascii1000.swapcase
