public void SetCallback(string eventName, IRelayProviderCallbackDelegate <T> callback)
 {
     this.Proxy.On <T>(eventName, (e) =>
     {
         callback?.Invoke(e);
     });
 }
 public void SetCallback(string eventName, IRelayProviderCallbackDelegate <T> callback)
 {
     this.Callback = callback;
 }