async Task IWhatsUpGroupMediator.BroadCastAsync(string message, IWhatsUpGroupMember whatsUpGroupMember)
 {
     foreach (var whatsupGroupMemberObj in whatsUpGroupMembersBag?.ToList())
     {
         if (whatsupGroupMemberObj != whatsUpGroupMember)
         {
             await whatsupGroupMemberObj?.ReceiveAsync(message);
         }
     }
 }
 Task IWhatsUpGroupMediator.RegisterAsync(IWhatsUpGroupMember whatsUpGroupMember)
 {
     return(Task.Run(() => whatsUpGroupMembersBag.Add(whatsUpGroupMember)));
 }