Access Vuforia Event Track handler along with Mono Behaviour

I have added a public class and along with mono develop, how can I add the ITrackableEventHandler?

How to access functions in Vuforia Event Handler?

Any help would be appreciated. Thanks.

Once you got all settled you can create a class that implements the ITrackingEventHandler:

public class MyTracker:ITrackingEventHandler{

    public event Action OnTrackingFounr=()=>{};
    public event Action OnTrackingLost=()=>{};
    void Start(){
        OnTrackingFound += TrackingFound;
        OnTrackingLost  += TrackingLost;
    }

    public void OnTrackableStateChanged(TrackableBehaviour.Status previousStatus, TrackableBehaviour.Status newStatus) {
        if(newStatus == TrackableBehaviour.Status.DETECTED || newStatus == TrackableBehaviour.Status.TRACKED || newStatus == TrackableBehaviour.Status.EXTENDED_TRACKED)
        {
             OnTrackingFound();	
        }else{
             OnTrackingLost();
        }
     }

}

OnTrackableStateChanged is called when vuforia detects a change. Then the rest is just spreading the info.
The events allow to spread the info to any listeners.