A second operation was started on this context instance before a previous operation completed. This is usually caused by different threads concurrently using the same instance of DbContext. For more information on how to avoid threading issues with DbContext, see https://go.microsoft.com/fwlink/?linkid=2097913.
at Microsoft.EntityFrameworkCore.Query.Internal.SingleQueryingEnumerable`1.Enumerator.MoveNext()
at System.Linq.Enumerable.TryGetSingle[TSource](IEnumerable`1 source, Boolean& found)
at lambda_method290(Closure, QueryContext)
at Bulev.Library.Orders.CartsRepository.GetAsync(Sessions session)
at Bulev.Library.Orders.CartsIM.ToActionResult(BaseController controller, Exception exception) in C:\_projects\Eltedi.ru\Bulev.Library.Orders\Models\Carts.cs:line 38