public async Task <Appointment> Handle(Query request, CancellationToken cancellationToken)
            {
                Appointment result = null;

                var appointmentSummary = (await _appointmentStorage.GetAppointmentSummaries())
                                         .FirstOrDefault(i => i.Id == request.Id);

                if (appointmentSummary != null)
                {
                    result = await _appointmentStorage.GetAppointment(request.Id);
                }

                return(result);
            }
 public async Task <AppointmentSummary[]> Handle(Query request, CancellationToken cancellationToken)
 {
     return(await _appointmentStorage.GetAppointmentSummaries());
 }