docs: add MessagePack release notes and expand README with XElement/Binary limitations

Changelog.md

@@ -1,3 +1,55 @@
+# 5.10.0 / AspNetCore 1.6.0 — MessagePack transport preview
+
+## AspNetCore 1.6.0
+
+* Added MessagePack wire-format support (`application/vnd.msgpack`) via [#591](https://github.com/OpenRIAServices/OpenRiaServices/pull/591)
+
+### Enable MessagePack on the server
+
+```csharp
+var builder = WebApplication.CreateBuilder(args);
+builder.Services.AddOpenRiaServices()
+    .AddMessagePackSerialization();
+```
+
+Optionally pass a custom `Nerdbank.MessagePack.MessagePackSerializer` to add converters or a custom comparer provider:
+
+```csharp
+builder.Services.AddOpenRiaServices()
+    .AddMessagePackSerialization(opt =>
+    {
+        opt.Serializer = new Nerdbank.MessagePack.MessagePackSerializer()
+        {
+            // custom converters / comparer provider
+        };
+    });
+```
+
+## Client (`OpenRiaServices.Client.DomainClients.Http`)
+
+* Added `MessagePackHttpDomainClientFactory` — a `DomainClientFactory` that communicates with the server using MessagePack over HTTP
+
+### Enable MessagePack on the client
+
+```csharp
+DomainContext.DomainClientFactory =
+    new MessagePackHttpDomainClientFactory(baseUri, httpClientFactory);
+```
+
+Optionally pass a custom serializer:
+
+```csharp
+var serializer = new MessagePackSerializer()
+{
+    // custom converters / comparer provider
+};
+
+DomainContext.DomainClientFactory =
+    new MessagePackHttpDomainClientFactory(baseUri, httpClientFactory, serializer);
+```
+
+For performance benchmark data see [PR #591](https://github.com/OpenRIAServices/OpenRiaServices/pull/591).
+
 # AspNetCore 1.5.0
 
 * Allow configuring Serializer security settings

src/OpenRiaServices.Hosting.AspNetCore/Framework/README.md

@@ -142,6 +142,26 @@ builder.Services.AddOpenRiaServices()
     .AddMessagePackSerialization();
 ```
 
+#### Known limitations
+
+The following types are **not** supported out of the box and require custom `MessagePackConverter<T>` implementations registered via `MessagePackSerializationOptions.Serializer.Converters`:
+
+- **`System.Xml.Linq.XElement`** — not handled by the default serializer. See the [XElementConverter sample](https://github.com/OpenRIAServices/OpenRiaServices/blob/main/src/Test/AspNetCoreWebsite/MessagePack/XElementConverter.cs) for a reference implementation that serialises the element as a plain XML string.
+- **`System.Data.Linq.Binary`** — not handled by the default serializer. See the [BinaryConverter sample](https://github.com/OpenRIAServices/OpenRiaServices/blob/main/src/Test/AspNetCoreWebsite/MessagePack/BinaryConverter.cs) for a reference implementation.
+
+Register the converters by passing a configuration callback:
+
+```csharp
+builder.Services.AddOpenRiaServices()
+    .AddMessagePackSerialization(opt =>
+    {
+        opt.Serializer = new Nerdbank.MessagePack.MessagePackSerializer()
+        {
+            Converters = [new XElementConverter(), new BinaryConverter()],
+        };
+    });
+```
+
 ### Configuring serializer security quotas
 
 You can configure reader quotas to limit resource consumption and mitigate denial-of-service (DoS) attacks.