IPictureCallback : I need help

Hi,

I'm trying to implement a camera view and allow the user to save a picture. I absolutely don't understand how callbacks work with Xamarin. The function takePicture needs a IPictureCallback, so I make a class with this interface. Here is the model :

public class CallbackTest : Camera.IPictureCallback
    {

        public void OnPictureTaken(byte[] data, Camera camera)
        {
            throw new NotImplementedException();
        }

        public IntPtr Handle
        {
        get { throw new NotImplementedException(); }
        }

        public void Dispose()
        {
        throw new NotImplementedException();
        }
    }

I understand I have to put my code which take a picture on OnPictureTaken. But what do I have to write in Handle and Dispose ?