@Override
  public Stream<byte[]> streamKeys(final SegmentIdentifier segmentIdentifier) {
    final RocksIterator rocksIterator = getDB().newIterator(safeColumnHandle(segmentIdentifier));
    rocksIterator.seekToFirst();
    return RocksDbIterator.create(rocksIterator).toStreamKeys();
  }
Safe method to map segment identifier to column handle.

@param segment segment identifier
@return column handle
plugins/rocksdb/src/main/java/org/hyperledger/besu/plugin/services/storage/rocksdb/segmented/RocksDBColumnarKeyValueStorage.java