@interface GroupActivities.Topic : _TtCs12_SwiftObject {
    void /* unknown type, empty encoding */ topic;
    void /* unknown type, empty encoding */ pubSubTopicGenerator;
    void /* unknown type, empty encoding */ cancellables;
    void /* unknown type, empty encoding */ stateMachine;
    void /* unknown type, empty encoding */ delegate;
    void /* unknown type, empty encoding */ subscription;
    void /* unknown type, empty encoding */ name;
    void /* unknown type, empty encoding */ receivedDataHandler;
    void /* unknown type, empty encoding */ pubSubStateChangedHandler;
    void /* unknown type, empty encoding */ catchupNeededHandler;
    void /* unknown type, empty encoding */ dataCryptor;
    void /* unknown type, empty encoding */ _subscribedParticipants;
    void /* unknown type, empty encoding */ invalidationHandler;
    void /* unknown type, empty encoding */ requestEncryptionKeysHandler;
    void /* unknown type, empty encoding */ seqNumWatermark;
    void /* unknown type, empty encoding */ pendingMessages;
    void /* unknown type, empty encoding */ pendingMessagesLock;
}

@end