anchor.diff:                }
               }
             } else if (_storageJdb?.supported ?? false) {
  -            _clear();
  +            _clearBeforeImport();
               var map = await _storageJdb.readMeta();
   
               if (Meta.isMapMeta(map)) {
  
positive.code: 
          await _findOrCreate();
          if (_storageBase.supported) {
            void _clear() {
              // empty stores and meta
              _meta = null;
              _mainStore = null;
              _stores.clear();
  
negative.code:             var corrupted = false;
  
              Future import(Stream<String> lines, {bool safeMode}) async {
                _clearBeforeImport();
                var firstLineRead = false;
  
                await for (var line in lines) {
                  _exportStat.lineCount++;
  