... range s ... (letter int32)
the letter at 0 is 't'
the letter at 1 is 'h'
the letter at 2 is 'i'
the letter at 3 is 's'
the letter at 4 is ':'
the letter at 5 is ' '
the letter at 6 is 'こ'
the letter at 9 is 'ん'
the letter at 12 is 'に'
the letter at 15 is 'ち'
the letter at 18 is 'は'
the letter at 21 is '.'
name = "this: こんにちは."
is 12 long

... range []rune(s) (letter rune)
the letter at 0 is 't'
the letter at 1 is 'h'
the letter at 2 is 'i'
the letter at 3 is 's'
the letter at 4 is ':'
the letter at 5 is ' '
the letter at 6 is 'こ'
the letter at 7 is 'ん'
the letter at 8 is 'に'
the letter at 9 is 'ち'
the letter at 10 is 'は'
the letter at 11 is '.'
name = "this: こんにちは."
is 12 long

... range []byte(s) (s byte)
the letter at 0 is 't'
the letter at 1 is 'h'
the letter at 2 is 'i'
the letter at 3 is 's'
the letter at 4 is ':'
the letter at 5 is ' '
the letter at 6 is 'ã'
the letter at 7 is ''
the letter at 8 is '“'
the letter at 9 is 'ã'
the letter at 10 is '‚'
the letter at 11 is '“'
the letter at 12 is 'ã'
the letter at 13 is ''
the letter at 14 is '«'
the letter at 15 is 'ã'
the letter at 16 is ''
the letter at 17 is '¡'
the letter at 18 is 'ã'
the letter at 19 is ''
the letter at 20 is '¯'
the letter at 21 is '.'
name = "this: こんにちは."
is 22 long

(spoiler)

....

> Think about what a rune is. A rune represents a Unicode code point, which can be composed of multiple bytes and also have different representations depending on the encoding.