presto-main/src/main/java/io/prestosql/operator/scalar/CharacterStringCasts.java/CharacterStringCasts/toCodePoints
class CharacterStringCasts:    private static List<Integer> toCodePoints(Slice slice)
    {
        ImmutableList.Builder<Integer> codePoints = ImmutableList.builder();
        for (int offset = 0; offset < slice.length(); ) {
            int codePoint = getCodePointAt(slice, offset);
            offset += lengthOfCodePoint(slice, offset);
            codePoints.add(codePoint);
        }
        return codePoints.build();
    }