// If sendHeartbeat throws, fetchNewEvents and cleanup should still be called
        final AtomicBoolean fetchCalled = new AtomicBoolean(false);
        final AtomicBoolean cleanupCalled = new AtomicBoolean(false);
        final CoordinatorHelper helper = new CoordinatorHelper() {
            @Override
            public void sendHeartbeat() {

                // Send periodic heartbeat
                sendHeartbeat(registration);
            }
        }
    }

    /**
     * Sends a heartbeat for the specified registration.
     *
     * @param registration the registration
     */
    private void sendHeartbeat(WitnessRegistration registration) {
        try {

     */
    @PostConstruct
    public void init() {
        instanceId = ComponentUtil.getSystemHelper().getInstanceId();
        lastEventCheckTime = System.currentTimeMillis();

        sendHeartbeat();

        final FessConfig fessConfig = ComponentUtil.getFessConfig();
        final int interval = fessConfig.getCoordinatorPollIntervalAsInteger();

            if (registration.getState() == WitnessRegistrationState.REGISTERED) {
                // Send periodic heartbeat
                sendHeartbeat(registration);
            }
        }
    }
    
    private void sendHeartbeat(WitnessRegistration registration) {
        try {
            WitnessHeartbeatRequest request = new WitnessHeartbeatRequest();