return !unicode.IsLower(r)
}

// trimUTF8 returns a length t as close to len(b) as possible such that b[:t]
// does not end in the middle of a possibly-valid UTF-8 sequence.
//
// If a large text buffer must be split before position i at the latest,
// splitting at position trimUTF(b[:i]) avoids splitting a UTF-8 sequence.
func trimUTF8(b []byte) int {
	// Scan backward to find non-continuation byte.