return b.err
	}
	if b.Available() <= 0 && b.Flush() != nil {
		return b.err
	}
	b.buf[b.n] = c
	b.n++
	return nil
}

// WriteRune writes a single Unicode code point, returning
// the number of bytes written and any error.
func (b *Writer) WriteRune(r rune) (size int, err error) {
	// Compare as uint32 to correctly handle negative runes.
	if uint32(r) < utf8.RuneSelf {
		err = b.WriteByte(byte(r))

		if (i != 0 || i == l-1) && ((i > 0 && rune(camel[i-1]) >= 'a') ||
			(i < l-1 && rune(camel[i+1]) >= 'a')) {
			b.WriteRune('_')
		}
		b.WriteRune(v + 'a' - 'A')
	}
	return b.String()