Add info about autoConfigureDataProtection

Author: Rick-Anderson

articles/container-apps/dotnet-overview.md

@@ -112,6 +112,8 @@ For a chance to implement custom logic to determine the health of your applicati
 
 By default, Azure Container Apps automatically scales your ASP.NET Core apps based on the number of incoming HTTP requests. You can also configure custom autoscaling rules based on other metrics, such as CPU or memory usage. To learn more about scaling, see [Set scaling rules in Azure Container Apps](scale-app.md).
 
+In .NET 8 and later, when a ASP.NET Core app that uses [Data Protection](/aspnet/core/security/data-protection/introduction) is deployed, the environment variable `autoConfigureDataProtection` is automatically set true. This setting starts a key manager and handles the writing and sharing keys across multiple instances when the app auto-scales. For more information, see [this GitHub pull request](https://github.com/Azure/azure-rest-api-specs/pull/28001). `autoConfigureDataProtection=true` allows ASP.NET Core apps that use Data Protection to scale horizontally when deployed to ACA by providing a default configuration.
+
 Autoscaling changes the number of replicas of your app based on the rules you define. By default, Container Apps randomly routes incoming traffic to the replicas of your ASP.NET Core app. Since traffic can split among different replicas, your app should be stateless so your application doesn't experience state-related issues.
 
 Features such as anti-forgery, authentication, SignalR, Blazor Server, and Razor Pages depend on data protection require extra configuration to work correctly when scaling to multiple replicas.