LeetCode #345 in Go: reverse vowels of a string, and how strings, bytes, and runes work in Go

The constraint-first choice between []byte and []rune is exactly the right lesson. One additional boundary is that a rune is a Unicode code point, not necessarily a user-perceived character: combining marks and emoji sequences can still span multiple runes. For this ASCII problem []byte is both simpler and faster; for production text, the requirement should say whether it operates on bytes, code points, or grapheme clusters. That specification matters more than choosing the most Unicode-looking type.