anchor.diff:  String _transformSource(LibraryElement reflectableLibrary,
                           LibraryElement capabilityLibrary,
                           List<ReflectableClassData> reflectableClasses,
  -                        Map<LibraryElement, Asset> libraryToAssetMap,
                           Map<LibraryElement, Set<LibraryElement>> missingImports,
                           TransformLogger logger,
                           ErrorReporter errorReporter,
  
positive.code:       "" : "\nimport 'package:reflectable/src/mirrors_unimpl.dart';";
    Set<LibraryElement> importsToAdd = missingImports[targetLibrary];
    if (importsToAdd != null) {
      AssetId targetId = libraryToAssetMap[targetLibrary].id;
      for (LibraryElement importToAdd in importsToAdd) {
        Uri importUri = resolver.getImportUri(importToAdd, from: targetId);
        print(importUri);
  
negative.code:   for (LibraryElement importer in requiredImporters) {
      Set<LibraryElement> importeds = requiredImports
          .where((_Import _import) => _import.importer == importer)
          .map((_Import _import) => _import.imported).toSet();
      result[importer] = importeds;
    }
  
  