    public void event(final ScopeEvent event)
    {
        switch (event) {
            case ENTER:
                if (value != null) {
                    MDC.put(MDC_TRACKING_KEY, value);
                }
                break;
            case LEAVE:
                MDC.remove(MDC_TRACKING_KEY);
                break;
        }
    }

    public void event(final ScopeEvent event)
    {
        switch (event) {
            case ENTER:
                if (value != null) {
                    MDC.put(MDC_TRACKING_KEY, value);
                }
                break;
            case LEAVE:
                MDC.remove(MDC_TRACKING_KEY);
                break;
            default:
                throw new IllegalStateException("Unknown Event: " + event);
        }
    }
