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

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

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