private final AtomicLong heartbeatsSent = new AtomicLong();
    private final AtomicLong registrationFailures = new AtomicLong();
    
    public void recordRegistration() { registrationsActive.incrementAndGet(); }
    public void recordUnregistration() { registrationsActive.decrementAndGet(); }
    public void recordNotification() { notificationsReceived.incrementAndGet(); }