Custom model binding to add XmlSerializer deserialization errors to model state (asp .net core mvc)

model binder.cs

// Thanks to : https://www.dotnetcurry.com/aspnet-mvc/1261/custom-model-binder-aspnet-mvc 
// and https://docs.microsoft.com/en-us/aspnet/core/mvc/advanced/custom-model-binding?view=aspnetcore-2.2

// model binder
 public class SmartXmlModelBinder : IModelBinder
    {
        public Task BindModelAsync(ModelBindingContext bindingContext)
        {
            try
            {
                var modelType = bindingContext.ModelType;
                var serializer = new XmlSerializer(modelType);
                var receivedStream = bindingContext.HttpContext.Request.Body;
                var modelValue = serializer.Deserialize(receivedStream);
                bindingContext.Result = ModelBindingResult.Success(modelValue);
            }
            catch (Exception ex)
            {
                bindingContext.ModelState.AddModelError("ModelError", $"{ex.Message} {ex.InnerException?.Message}");
            }
            return Task.CompletedTask;

        }
    }
    
    // model binder provider
    public class SmartXmlModelBinderProvider : IModelBinderProvider
    {

        public IModelBinder GetBinder(ModelBinderProviderContext context)
        {
            return new SmartXmlModelBinder();
        }
    }
    
    // Startup.cs
    services.AddMvc(
                opts =>
                {
                    // ... other usual options ...
                    // add custom binder to beginning of collection
                    opts.ModelBinderProviders.Insert(0, new SmartXmlModelBinderProvider());
                }