void onCallRejected(SmbCircuitBreaker circuitBreaker);
    }

    /**
     * Add a listener for circuit breaker events
     *
     * @param listener the listener to add
     */
    public void addListener(CircuitBreakerListener listener) {
        if (listener != null) {
            listeners.add(listener);
        }
    }

    /**
     * Remove a listener
     *

        FtpServerFactory factory = new FtpServerFactory();
        ListenerFactory lisnerFactory = new ListenerFactory();
        lisnerFactory.setPort(port);
        factory.addListener("default", lisnerFactory.createListener());

        if (username != null) {
            UserManager userManager = factory.getUserManager();
            BaseUser ftpUser = new BaseUser();