@BeforeExperiment
  void setUp() {
    collection = source.supplier.get();
    for (int i = 0; i < size; i++) {
      collection.add(new Object());
    }
  }

  @Benchmark
  int runOperation(int reps) {
    int result = 0;
    for (int i = 0; i < reps; i++) {
      result += System.identityHashCode(operation.operate(collection.stream()));
    }
    return result;
  }