SignalR hub.on method not starting in Android

Question

I am trying to implement a SignalR client in an Android application. but hub.on ("method name") does not work.

Platform.loadPlatformComponent( new AndroidPlatformComponent() );
String host = "...";
String qs = "....";
HubConnection connection = new HubConnection(...);
HubProxy hub = connection.createHubProxy( ... );

I tried the following 2 subscription options

Option 1

hub.on( "testMessage", new SubscriptionHandler1< CustomMessage >() {
    @Override
    public void run(CustomMessage msg) {

        Log.d("result := ", msg.text);
        Toast.makeText(MainActivity.this, msg.text, Toast.LENGTH_LONG).show();
    }
}, CustomMessage.class);

Option 2

....
hub.subscribe("testMessage");
....
Handler handler = new Handler();

public void addMessage( CustomMessage msg ) {

    final String fStatus = msg.text;
    handler.post(new Runnable(){

        @Override
        public void run() {

            Toast.makeText(MainActivity.this, fStatus, Toast.LENGTH_LONG).show()
        }
    });
}

I get the following log messages

Verbose – serverSentEvents – Found new data:data: {}
Verbose – serverSentEvents – Trigger onData: {}
Verbose – HubConnection – Received data;