Query Firebase Value OnChange - xamarin

Question

I am trying to register a Xamarin app to listen for value changes on a particular value change. I can access the value, but for some reason when I listen to the value change, it will fire once but never again until I reboot.
I am using Xamarin Studio, and FireSharp libraries. This is the API code in the C# library portion of the app. The reason I have removed the delegate was to check if it wasn't the delegate being cleaned up after the first call or something.
public class ValueAPI
{
private IFirebaseClient _client;
private ITemperatureListener _listener;
private EventStreamResponse _response;
public ValueAPI()
{
IFirebaseConfig config = new FirebaseConfig
{
AuthSecret = "...",
BasePath = "https://[value-api].firebaseio.com/"
};
_client = new FirebaseClient(config);
}
public async Task<string> getValue()
{
FirebaseResponse response = await _client.GetAsync("VALUE");
return response.Body;
}
public async Task<string> registerForUpdates(IValueListener listener)
{
_listener = listener;
_response = await _client.OnAsync("VALUE", null, this.OnValueChange, null, null);
return _response.ToString();
}
private void OnValueChange(object sender, ValueChangedEventArgs args, object context)
{
if (_listener != null)
{
_listener.OnValueUpdated(args.Data);
}
}
}
ANDROID CODE
ValueAPI api = new ValueAPI();
protected override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
// Set our view from the "main" layout resource
SetContentView(Resource.Layout.Main);
getValue();
getValueUpdates();
}
private async void getValue()
{
Task<string> task = api.getValue();
string result = await task;
TextView label = (TextView)FindViewById(Resource.Id.label_value);
label.Text = result;
}
private async void getValueUpdates()
{
Task<string> task = api.registerForUpdates(this);
await task;
}
public void OnValueUpdated(string value)
{
TextView label = (TextView)FindViewById(Resource.Id.label_value_updated);
label.Text = value;
}