anchor.diff:        assert(method == methodName);
         dynamic caughtException;
         StackTrace caughtStack;
  -      Map<String, String> result;
  +      Map<String, dynamic> result;
         try {
           result = await callback(parameters);
         } catch (exception, stack) {
  
positive.code:       callback: (Map<String, String> parameters) async {
          if (parameters.containsKey('enabled'))
            await setter(parameters['enabled'] == 'true');
          return <String, String>{ 'enabled': await getter() ? 'true' : 'false' };
        }
      );
    }
  
negative.code:       callback: (Map<String, String> parameters) async {
          if (parameters.containsKey('value'))
            await setter(parameters['value']);
          return <String, dynamic>{ 'value': await getter() };
        }
      );
    }
  