@Benchmark
  long add(int reps) throws ExecutionException, InterruptedException {
    return doMultithreadedLoop(
        new Callable<Long>() {
          @Override
          public Long call() {
            return runAddSingleThread(reps);
          }
        });
  }

  @Benchmark
  long addRemove(int reps) throws ExecutionException, InterruptedException {
    return doMultithreadedLoop(
        new Callable<Long>() {