public SignalingOfferNotification(ISignalingOfferPayload payload)
 {
     Type     = payload.Type;
     Receiver = payload.Receiver;
     Sender   = payload.Sender;
     Sdp      = payload.Sdp;
 }
 public async Task Offer(ISignalingOfferPayload payload)
 {
     await _mediator.Publish(new SignalingOfferNotification(payload));
 }