message: Fix database connection leak
diff: @@ -75,6 +75,11 @@ class LMDBDatasetOp::Dataset : public DatasetBase {
  explicit Iterator(const Params& params)
  : DatasetIterator<Dataset>(params) {}
  + virtual ~Iterator() {
  + // Close any open database connections.
  + ResetStreamsLocked();
  + }
  +
  Status GetNextInternal(IteratorContext* ctx,
  std::vector<Tensor>* out_tensors,
  bool* end_of_sequence) override {
  @@ -108,6 +113,7 @@ class LMDBDatasetOp::Dataset : public DatasetBase {
  }
  if (current_file_index_ == dataset()->filenames_.size()) {
  *end_of_sequence = true;
  + ResetStreamsLocked();
  return Status::OK();
  }
  