Add Google Protocol Buffers serialization documentation for Orleans

docs/orleans/host/configuration-guide/serialization-configuration.md

@@ -48,6 +48,23 @@ siloBuilder.Services.AddSerializer(serializerBuilder =>
 });
 ```
 
+## Configure Orleans to use Google Protocol Buffers
+
+To configure Orleans to use Google Protocol Buffers (Protobuf) to serialize your types, reference the [Microsoft.Orleans.Serialization.Protobuf](https://nuget.org/packages/Microsoft.Orleans.Serialization.Protobuf) NuGet package. Then, configure the serializer, specifying which types it will be responsible for. In the following example, we specify that the Protobuf serializer is responsible for all types in the `Example.Namespace` namespace.
+
+- Install the [Microsoft.Orleans.Serialization.Protobuf](https://nuget.org/packages/Microsoft.Orleans.Serialization.Protobuf) NuGet package.
+- Configure the serializer using the <xref:Orleans.Serialization.SerializationHostingExtensions.AddProtobufSerializer%2A> method.
+
+Consider the following example when interacting with the <xref:Orleans.Hosting.ISiloBuilder>:
+
+```csharp
+siloBuilder.Services.AddSerializer(serializerBuilder =>
+{
+    serializerBuilder.AddProtobufSerializer(
+        isSupported: type => type.Namespace.StartsWith("Example.Namespace"));
+});
+```
+
 :::zone-end
 
 <!-- markdownlint-disable MD044 -->

docs/orleans/host/configuration-guide/serialization-customization.md

@@ -16,10 +16,11 @@ One important aspect of Orleans is its support for customization of serializatio
 :::zone target="docs" pivot="orleans-7-0"
 <!-- markdownlint-enable MD044 -->
 
-Orleans provides two serializer implementations:
+Orleans provides three serializer implementations:
 
 - [Microsoft.Orleans.Serialization.SystemTextJson](https://nuget.org/packages/Microsoft.Orleans.Serialization.SystemTextJson)
 - [Microsoft.Orleans.Serialization.NewtonsoftJson](https://nuget.org/packages/Microsoft.Orleans.Serialization.NewtonsoftJson)
+- [Microsoft.Orleans.Serialization.Protobuf](https://nuget.org/packages/Microsoft.Orleans.Serialization.Protobuf)
 
 To configure either of these packages, see [Serialization configuration in Orleans](serialization-configuration.md?pivots=orleans-7-0).