@Override
        public void run() {
            LocalInstance<IntWrapper, IntWrapper> s = r.getLocalInstance();
            IntWrapper w = new IntWrapper();
            for (int i = 0; i < ITERATIONS; ++i) {
                w.counter = i;
                r.update(w, s);
            }
        }
Benchmark to compare ThreadLocalDirectory with java.util.concurrent's atomic
variables. Very low precision since it's an adapted unit test.

@author <a href="mailto:steinar@yahoo-inc.com">Steinar Knutsen</a>
vespajlib/developernotes/ThreadLocalDirectoryBenchmark.java