WitnessRpcClient mockRpc = mock(WitnessRpcClient.class);
        lenient().when(mockRpc.register(any(WitnessRegisterRequest.class))).thenReturn(registerResponse);
        lenient().when(mockRpc.unregister(any(WitnessUnregisterRequest.class))).thenReturn(unregisterResponse);

        TestWitnessClient client = new TestWitnessClient(witnessServer, mockContext, mockRpc);

        TestNotificationListener listener = new TestNotificationListener();

        return CompletableFuture.runAsync(() -> {
            try {
                registration.setState(WitnessRegistrationState.UNREGISTERING);
                
                WitnessUnregisterRequest request = new WitnessUnregisterRequest();
                request.setRegistrationId(registration.getRegistrationId());
                
                WitnessUnregisterResponse response = rpcClient.unregister(request);
                

        return CompletableFuture.runAsync(() -> {
            try {
                registration.setState(WitnessRegistrationState.UNREGISTERING);

                WitnessUnregisterRequest request = new WitnessUnregisterRequest();
                request.setRegistrationId(registration.getRegistrationId());

                WitnessUnregisterResponse response = rpcClient.unregister(request);

     *
     * @param request the unregistration request
     * @return the unregistration response
     * @throws IOException if the RPC call fails
     */
    public WitnessUnregisterResponse unregister(WitnessUnregisterRequest request) throws IOException {
        if (!connected) {
            throw new IOException("Witness client not connected");
        }

        try {