public List<Announcement> Get(GetAnnouncementsRequest request)
 {
     Thread.Sleep(2000);
     return new List<Announcement>
     {
        new Announcement{
            Id = 1,
            Content="Server-side Announcement1"
        },
        new Announcement{
            Id = 2,
         Content = "Server-side Announcement2"
        }
     };
 }
 public async Task <IActionResult> GetAnnouncements([FromQuery] GetAnnouncementsRequest request)
 => await Mediator
 .Send(new GetDefaultQuery <AnnouncementResponse>(request, ApiRoutes.Announcements.Get))
 .ToOkResult();