private void SendServerState(string state)
 {
     ServerStateChanged?.Invoke(this,
                                new Services.ServerStateChanged
     {
         State = state
     });
 }
 private void SendServerState()
 {
     ServerStateChanged?.Invoke(this,
                                new Services.ServerStateChanged
     {
         ListenerState = _receiver?.State,
         SenderState   = null
     });
 }