private double mean(long[] values) {
        long sum = 0L;

        // ignore overflow :)
        for (long v : values) {
            sum += v;
        }
        return ((double) sum / (double) values.length);
    }
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