anchor.diff:  
     Future fetch() async {
       Future<Map> load(String path) async {
  -      _logger.info('Loading popularity data: $path');
  +      _logger.info('Loading popularity data: ${_bucketUri(bucket, path)}');
         try {
           Stream<List<int>> stream = bucket.read(path);
           if (path.endsWith('.gz')) {
  
positive.code:             .transform(JSON.decoder)
              .single;
        } catch (e, st) {
          _logger.severe('Unable to load popularity data: $path', e, st);
        }
        return null;
      }
  
negative.code:             .single;
          return new SearchSnapshot.fromJson(json);
        } catch (e, st) {
          _logger.severe(
              'Unable to load search snapshot: ${_bucketUri(bucket, path)}',
              e,
              st);
        }
        return null;
      }
  