static String generateFieldName(Random random) {
        int len = random.nextInt(100) + 3;
        char[] base = new char[len];
        for (int i = 0; i < len; ++i) {
            base[i] = (char) (random.nextInt(26) + 'a');
        }
        return new String(base);
    }
Object identity is used to differentiate between different implementation strategies, toString() is used to print a report.

@return an object with a descriptive toString() for the implementation under test
vespajlib/src/test/java/com/yahoo/text/JsonMicroBenchmarkTestCase.java