public static char lowSurrogate(int codePoint) {
        return (char) ((codePoint & 0x3ff) + MIN_LOW_SURROGATE);
    }
Reads the string from a byte[] using that was encoded a using Modified UTF-8 format. Additionally supports
4-byte surrogates, de-serializing them as surrogate pairs.

See: http://en.wikipedia.org/wiki/UTF-8#Description for encoding details.
protostuff-api/src/main/java/io/protostuff/StringSerializer.java