return nil
}

// WriteRune appends the UTF-8 encoding of Unicode code point r to the
// buffer, returning its length and an error, which is always nil but is
// included to match [bufio.Writer]'s WriteRune. The buffer is grown as needed;
// if it becomes too large, WriteRune will panic with [ErrTooLarge].
func (b *Buffer) WriteRune(r rune) (n int, err error) {
	// Compare as uint32 to correctly handle negative runes.
	if uint32(r) < utf8.RuneSelf {