get method
Look up a row by primary key. Returns null if absent.
Implementation
Future<Map<String, Object?>?> get(Object pkVal) async {
final pkBytes = _encodePrimaryKey(pkVal);
final rowId = await _index.get(pkBytes);
if (rowId == null) return null;
final bytes = await _heap.get(rowId);
if (bytes == null) return null;
return _decodeRow(bytes);
}