1:  41 42 43 ae 58 59 5a       --> is not utf8
 2:  41 42 43 ae 58 59 5a       --> is not utf8
 3:  ae --> is not utf8
 4:  ae --> is not utf8
 5:  c2 ae      --> is utf8
 6:  41 42 43 c2 ae 58 59 5a    --> is utf8
 7:  41 42 43 c2 ae 58 59 5a    --> is utf8
 8:  41 42 43 c2 ae 58 59 5a    --> is not utf8     # wrong
 9:  41 42 43 c2 ae 58 59 5a    --> is utf8
10:  41 42 43 c2 ae 58 59 5a    --> is not utf8     # wrong
11:  41 42 43 ae 58 59 5a       --> is not utf8
12:  41 42 43 ae 58 59 5a       --> is utf8         # WRONG