SSE return types /2

Author: Rick-Anderson

aspnetcore/fundamentals/minimal-apis/responses.md

@@ -120,14 +120,28 @@ In order to document this endpoint correctly the extension method `Produces` is
 
 :::code language="csharp" source="~/fundamentals/minimal-apis/9.0-samples/Snippets/Program.cs" id="snippet_04":::
 
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 ### Built-in results
 
 [!INCLUDE [results-helpers](~/fundamentals/minimal-apis/includes/results-helpers.md)]
 
 The following sections demonstrate the usage of the common result helpers.
 
+#### Server-Sent Events (SSE)
+
+The [TypedResults.ServerSentEvents](https://source.dot.net/#Microsoft.AspNetCore.Http.Results/TypedResults.cs,051e6796e1492f84) API supports returning a [ServerSentEvents](xref:System.Net.ServerSentEvents) result.
+
+[Server-Sent Events](https://developer.mozilla.org/docs/Web/API/Server-sent_events) is a server push technology that allows a server to send a stream of event messages to a client over a single HTTP connection. In .NET, the event messages are represented as [`SseItem<T`>`](/dotnet/api/system.net.serversentevents.sseitem-1) objects, which may contain an event type, an ID, and a data payload of type `T`.
+
+The [TypedResults](xref:Microsoft.AspNetCore.Http.TypedResults) class has a static method called [ServerSentEvents](https://source.dot.net/#Microsoft.AspNetCore.Http.Results/TypedResults.cs,ceb980606eb9e295) that can be used to return a `ServerSentEvents` result. The first parameter to this method is an `IAsyncEnumerable<SseItem<T>>` that represents the stream of event messages to be sent to the client.
+
+The following example illustrates how to use the `TypedResults.ServerSentEvents` API to return a stream of heart rate events as JSON objects to the client:
+
+:::code language="csharp" source="~/fundamentals/minimal-apis/10.0-samples/MinimalServerSentEvents/Program.cs" id="snippet_json" :::
+
+For more information, see the [Minimal API sample app](https://github.com/dotnet/AspNetCore.Docs/blob/main/aspnetcore/fundamentals/minimal-apis/10.0-samples/MinimalServerSentEvents/Program.cs) using the `TypedResults.ServerSentEvents` API to return a stream of heart rate events as string, `ServerSentEvents`, and JSON objects to the client.
+
 #### JSON
 
 :::code language="csharp" source="~/fundamentals/minimal-apis/9.0-samples/Snippets/Program.cs" id="snippet_05":::
@@ -150,6 +164,8 @@ The preceding example returns a 500 status code.
 
 :::code language="csharp" source="~/fundamentals/minimal-apis/9.0-samples/Snippets/Program.cs" id="snippet_12":::
 
+#### Problem
+
 #### Text
 
 :::code language="csharp" source="~/fundamentals/minimal-apis/9.0-samples/Snippets/Program.cs" id="snippet_08":::