IProblemDetailsWriter (#27255)

* IProblemDetailsWriter

* IProblemDetailsWriter

Author: Rick-Anderson

aspnetcore/web-api/handle-errors.md

@@ -5,7 +5,7 @@ description: Learn about error handling with ASP.NET Core web APIs.
 monikerRange: '>= aspnetcore-3.1'
 ms.author: riande
 ms.custom: mvc
-ms.date: 9/23/2022
+ms.date: 10/14/2022
 uid: web-api/handle-errors
 ---
 # Handle errors in ASP.NET Core web APIs
@@ -292,6 +292,12 @@ An alternative to a [custom exception handler page](xref:fundamentals/error-hand
 
 [Hellang.Middleware.ProblemDetails](https://www.nuget.org/packages/Hellang.Middleware.ProblemDetails/) is a 3rd party problem details middleware Nuget package.
 
+### Implement `IProblemDetailsWriter`
+
+An <xref:Microsoft.AspNetCore.Http.IProblemDetailsWriter> implementation can be created for advanced customizations:
+
+:::code language="csharp" source="~/../AspNetCore.Docs.Samples/fundamentals/middleware/problem-details-service/SampleProblemDetailsWriter.cs" :::
+
 ### Implement `ProblemDetailsFactory`
 
 MVC uses <xref:Microsoft.AspNetCore.Mvc.Infrastructure.ProblemDetailsFactory?displayProperty=fullName> to produce all instances of <xref:Microsoft.AspNetCore.Mvc.ProblemDetails> and <xref:Microsoft.AspNetCore.Mvc.ValidationProblemDetails>. This factory is used for: