Method NewIterator

src/leveldb/db/db_test.cc:2042–2052

    return Status::NotFound(key);
  }
  Iterator* NewIterator(const ReadOptions& options) override {
    if (options.snapshot == nullptr) {
      KVMap* saved = new KVMap;
      *saved = map_;
      return new ModelIter(saved, true);
    } else {
      const KVMap* snapshot_state =
          &(reinterpret_cast<const ModelSnapshot*>(options.snapshot)->map_);
      return new ModelIter(snapshot_state, false);
    }
  }
  const Snapshot* GetSnapshot() override {
    ModelSnapshot* snapshot = new ModelSnapshot;
    snapshot->map_ = map_;