StackOverFlow exception GeckoFx

Question

Hi there,

I am using GeckoFX Multi 1.9.1.0 v.1 GeckoMulti and implementing the HttpActivityDistributor and HttpActivityObserver by using the following code:

public void InitObserver()
        {
nsIHttpActivityDistributor activityDistributor = Xpcom.GetService<nsIHttpActivityDistributor>("@mozilla.org/network/http-activity-distributor;1");
                activityDistributor = Xpcom.QueryInterface<nsIHttpActivityDistributor>(activityDistributor);
                GeckoHttpActivityObserver httpActivityObserver = new GeckoHttpActivityObserver();
                activityDistributor.addObserver(httpActivityObserver);
}

This is the httpAcitvityDistributor and httpActivityObserver interface:

[Guid("7C512CB8-582A-4625-B5B6-8639755271B5"), ComImport, InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
    interface nsIHttpActivityDistributor : nsIHttpActivityObserver
    {
        void addObserver(nsIHttpActivityObserver aObserver);
        void removeObserver(nsIHttpActivityObserver aObserver);
    }

[Guid("412880C8-6C36-48d8-BF8F-84F91F892503"), ComImport, InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]    
    interface nsIHttpActivityObserver
    {
    void observeActivity(nsISupports  aHttpChannel,
                         UInt32 aActivityType,
                         UInt32 aActivitySubtype,
                         UInt64 aTimestamp,
                         UInt64 aExtraSizeData,
                         nsACString aExtraStringData);

    bool get_isActive();
    }

And this is the httpActivityObserver implementation

public class GeckoHttpActivityObserver : nsIHttpActivityObserver
    { 
        public GeckoHttpActivityObserver() { }

        public void observeActivity(Skybound.Gecko.nsISupports aHttpChannel, UInt32 aActivityType, UInt32 aActivitySubtype, UInt64 aTimestamp, UInt64 aExtraSizeData, nsACString aExtraStringData) 
        {            
                ulong bytesSent;
                ulong bytesReceived;              

                if (aActivityType == nsIHttpActivityObserverConstants.ACTIVITY_TYPE_SOCKET_TRANSPORT && aActivitySubtype == nsISocketTransportConstants.STATUS_SENDING_TO)
                    bytesSent = aExtraSizeData;

                if (aActivityType == nsIHttpActivityObserverConstants.ACTIVITY_TYPE_HTTP_TRANSACTION && aActivitySubtype == nsIHttpActivityObserverConstants.ACTIVITY_SUBTYPE_RESPONSE_COMPLETE)
                    bytesReceived = aExtraSizeData;                           
        }       

        public bool get_isActive() 
        {
            bool value = false;
            return value;
        }

    }

Now on, I am getting a stack overflow exception when try to execute the activityDistributor.addObserver(httpActivityObserver) described at InitObserver() method.

Did I miss something?

Thank you so much in advance for your help and support

Regards