@Override
  public void close() throws IOException {
    if (closed.compareAndSet(false, true)) {
      closed.set(true);
      readOptions.close();
      snapshot.close();
    }
  }
Instantiates a new RocksDb columnar key value snapshot.

@param db the db
@param metrics the metrics
plugins/rocksdb/src/main/java/org/hyperledger/besu/plugin/services/storage/rocksdb/segmented/RocksDBColumnarKeyValueSnapshot.java