anchor.diff:              FileSystemEntity.isFileSync(entity.path) &&
               entity.path != assetPath) {
             String key = path.relative(entity.path, from: baseAsset.base);
  -          variants.add(new _Asset(base: baseAsset.base, key: key));
  +          String assetEntry;
  +          if (baseAsset.symbolicPrefix != null)
  +            assetEntry = path.join(baseAsset.symbolicPrefix, key);
  +          variants.add(new _Asset(base: baseAsset.base, assetEntry: assetEntry, relativePath: key));
           }
         }
       }
  
positive.code:       result.add(new _Asset(
          base: '${ArtifactStore.flutterRoot}/bin/cache/artifacts/material_fonts',
          source: path.basename(assetKey),
          key: assetKey
        ));
      }
    }
  
negative.code: }
  
  ZipEntry _createAssetEntry(_Asset asset) {
    String source = asset.source ?? asset.relativePath;
    File file = new File('${asset.base}/$source');
    if (!file.existsSync()) {
      printError('Cannot find asset "$source" in directory "${path.absolute(asset.base)}".');
      return null;
    }
    return new ZipEntry.fromFile(asset.assetEntry, file);
  }
  
  ZipEntry _createAssetManifest(Map<_Asset, List<_Asset>> assets) {
  