public int skip(int codePointCount, int start) {
        int index = start;
        for (int i = 0; i < codePointCount; i++) {
            index = nextIndex(index);
            if (index > s.length()) break;
        }
        return index;
    }
Returns the position count code points after start (which may be past the end of the string)
vespajlib/src/main/java/com/yahoo/text/UnicodeString.java