public async Task DoorBellResponse([FromBody] DoorBellResponseModel dto)
        {
            var delivery = await context.Delivery
                           .Include(d => d.CourierToken)
                           .FirstOrDefaultAsync(d => d.PackageId == dto.PackageId);

            if (delivery?.CourierToken == null)
            {
                return;
            }

            await firebase.SendNotification(
                delivery.CourierToken.Token,
                new Dictionary <string, string>
            {
                { "MessageType", nameof(DoorBellResponse) },
                { nameof(DoorBellModel.PackageId), dto.PackageId },
                { nameof(DoorBellResponseModel.IsAvailable), dto.IsAvailable.ToString() }
            });
        }