feat: add sitestream.proto definition and generated gRPC stubs

Define the SiteStreamService proto for real-time instance event
streaming (attribute value changes, alarm state changes) from site
nodes to central. Add pre-generated C# stubs following the existing
LmxProxy pattern, gRPC NuGet packages with FrameworkReference for
ASP.NET Core server types, and proto roundtrip tests.

src/ScadaLink.Communication/SiteStreamGrpc/SitestreamGrpc.cs

@@ -0,0 +1,145 @@
+// <auto-generated>
+//     Generated by the protocol buffer compiler.  DO NOT EDIT!
+//     source: sitestream.proto
+// </auto-generated>
+#pragma warning disable 0414, 1591, 8981, 0612
+#region Designer generated code
+
+using grpc = global::Grpc.Core;
+
+namespace ScadaLink.Communication.Grpc {
+  public static partial class SiteStreamService
+  {
+    static readonly string __ServiceName = "sitestream.SiteStreamService";
+
+    [global::System.CodeDom.Compiler.GeneratedCode("grpc_csharp_plugin", null)]
+    static void __Helper_SerializeMessage(global::Google.Protobuf.IMessage message, grpc::SerializationContext context)
+    {
+      #if !GRPC_DISABLE_PROTOBUF_BUFFER_SERIALIZATION
+      if (message is global::Google.Protobuf.IBufferMessage)
+      {
+        context.SetPayloadLength(message.CalculateSize());
+        global::Google.Protobuf.MessageExtensions.WriteTo(message, context.GetBufferWriter());
+        context.Complete();
+        return;
+      }
+      #endif
+      context.Complete(global::Google.Protobuf.MessageExtensions.ToByteArray(message));
+    }
+
+    [global::System.CodeDom.Compiler.GeneratedCode("grpc_csharp_plugin", null)]
+    static class __Helper_MessageCache<T>
+    {
+      public static readonly bool IsBufferMessage = global::System.Reflection.IntrospectionExtensions.GetTypeInfo(typeof(global::Google.Protobuf.IBufferMessage)).IsAssignableFrom(typeof(T));
+    }
+
+    [global::System.CodeDom.Compiler.GeneratedCode("grpc_csharp_plugin", null)]
+    static T __Helper_DeserializeMessage<T>(grpc::DeserializationContext context, global::Google.Protobuf.MessageParser<T> parser) where T : global::Google.Protobuf.IMessage<T>
+    {
+      #if !GRPC_DISABLE_PROTOBUF_BUFFER_SERIALIZATION
+      if (__Helper_MessageCache<T>.IsBufferMessage)
+      {
+        return parser.ParseFrom(context.PayloadAsReadOnlySequence());
+      }
+      #endif
+      return parser.ParseFrom(context.PayloadAsNewBuffer());
+    }
+
+    [global::System.CodeDom.Compiler.GeneratedCode("grpc_csharp_plugin", null)]
+    static readonly grpc::Marshaller<global::ScadaLink.Communication.Grpc.InstanceStreamRequest> __Marshaller_sitestream_InstanceStreamRequest = grpc::Marshallers.Create(__Helper_SerializeMessage, context => __Helper_DeserializeMessage(context, global::ScadaLink.Communication.Grpc.InstanceStreamRequest.Parser));
+    [global::System.CodeDom.Compiler.GeneratedCode("grpc_csharp_plugin", null)]
+    static readonly grpc::Marshaller<global::ScadaLink.Communication.Grpc.SiteStreamEvent> __Marshaller_sitestream_SiteStreamEvent = grpc::Marshallers.Create(__Helper_SerializeMessage, context => __Helper_DeserializeMessage(context, global::ScadaLink.Communication.Grpc.SiteStreamEvent.Parser));
+
+    [global::System.CodeDom.Compiler.GeneratedCode("grpc_csharp_plugin", null)]
+    static readonly grpc::Method<global::ScadaLink.Communication.Grpc.InstanceStreamRequest, global::ScadaLink.Communication.Grpc.SiteStreamEvent> __Method_SubscribeInstance = new grpc::Method<global::ScadaLink.Communication.Grpc.InstanceStreamRequest, global::ScadaLink.Communication.Grpc.SiteStreamEvent>(
+        grpc::MethodType.ServerStreaming,
+        __ServiceName,
+        "SubscribeInstance",
+        __Marshaller_sitestream_InstanceStreamRequest,
+        __Marshaller_sitestream_SiteStreamEvent);
+
+    /// <summary>Service descriptor</summary>
+    public static global::Google.Protobuf.Reflection.ServiceDescriptor Descriptor
+    {
+      get { return global::ScadaLink.Communication.Grpc.SitestreamReflection.Descriptor.Services[0]; }
+    }
+
+    /// <summary>Base class for server-side implementations of SiteStreamService</summary>
+    [grpc::BindServiceMethod(typeof(SiteStreamService), "BindService")]
+    public abstract partial class SiteStreamServiceBase
+    {
+      [global::System.CodeDom.Compiler.GeneratedCode("grpc_csharp_plugin", null)]
+      public virtual global::System.Threading.Tasks.Task SubscribeInstance(global::ScadaLink.Communication.Grpc.InstanceStreamRequest request, grpc::IServerStreamWriter<global::ScadaLink.Communication.Grpc.SiteStreamEvent> responseStream, grpc::ServerCallContext context)
+      {
+        throw new grpc::RpcException(new grpc::Status(grpc::StatusCode.Unimplemented, ""));
+      }
+
+    }
+
+    /// <summary>Client for SiteStreamService</summary>
+    public partial class SiteStreamServiceClient : grpc::ClientBase<SiteStreamServiceClient>
+    {
+      /// <summary>Creates a new client for SiteStreamService</summary>
+      /// <param name="channel">The channel to use to make remote calls.</param>
+      [global::System.CodeDom.Compiler.GeneratedCode("grpc_csharp_plugin", null)]
+      public SiteStreamServiceClient(grpc::ChannelBase channel) : base(channel)
+      {
+      }
+      /// <summary>Creates a new client for SiteStreamService that uses a custom <c>CallInvoker</c>.</summary>
+      /// <param name="callInvoker">The callInvoker to use to make remote calls.</param>
+      [global::System.CodeDom.Compiler.GeneratedCode("grpc_csharp_plugin", null)]
+      public SiteStreamServiceClient(grpc::CallInvoker callInvoker) : base(callInvoker)
+      {
+      }
+      /// <summary>Protected parameterless constructor to allow creation of test doubles.</summary>
+      [global::System.CodeDom.Compiler.GeneratedCode("grpc_csharp_plugin", null)]
+      protected SiteStreamServiceClient() : base()
+      {
+      }
+      /// <summary>Protected constructor to allow creation of configured clients.</summary>
+      /// <param name="configuration">The client configuration.</param>
+      [global::System.CodeDom.Compiler.GeneratedCode("grpc_csharp_plugin", null)]
+      protected SiteStreamServiceClient(ClientBaseConfiguration configuration) : base(configuration)
+      {
+      }
+
+      [global::System.CodeDom.Compiler.GeneratedCode("grpc_csharp_plugin", null)]
+      public virtual grpc::AsyncServerStreamingCall<global::ScadaLink.Communication.Grpc.SiteStreamEvent> SubscribeInstance(global::ScadaLink.Communication.Grpc.InstanceStreamRequest request, grpc::Metadata headers = null, global::System.DateTime? deadline = null, global::System.Threading.CancellationToken cancellationToken = default(global::System.Threading.CancellationToken))
+      {
+        return SubscribeInstance(request, new grpc::CallOptions(headers, deadline, cancellationToken));
+      }
+      [global::System.CodeDom.Compiler.GeneratedCode("grpc_csharp_plugin", null)]
+      public virtual grpc::AsyncServerStreamingCall<global::ScadaLink.Communication.Grpc.SiteStreamEvent> SubscribeInstance(global::ScadaLink.Communication.Grpc.InstanceStreamRequest request, grpc::CallOptions options)
+      {
+        return CallInvoker.AsyncServerStreamingCall(__Method_SubscribeInstance, null, options, request);
+      }
+      /// <summary>Creates a new instance of client from given <c>ClientBaseConfiguration</c>.</summary>
+      [global::System.CodeDom.Compiler.GeneratedCode("grpc_csharp_plugin", null)]
+      protected override SiteStreamServiceClient NewInstance(ClientBaseConfiguration configuration)
+      {
+        return new SiteStreamServiceClient(configuration);
+      }
+    }
+
+    /// <summary>Creates service definition that can be registered with a server</summary>
+    /// <param name="serviceImpl">An object implementing the server-side handling logic.</param>
+    [global::System.CodeDom.Compiler.GeneratedCode("grpc_csharp_plugin", null)]
+    public static grpc::ServerServiceDefinition BindService(SiteStreamServiceBase serviceImpl)
+    {
+      return grpc::ServerServiceDefinition.CreateBuilder()
+          .AddMethod(__Method_SubscribeInstance, serviceImpl.SubscribeInstance).Build();
+    }
+
+    /// <summary>Register service method with a service binder with or without implementation. Useful when customizing the service binding logic.
+    /// Note: this method is part of an experimental API that can change or be removed without any prior notice.</summary>
+    /// <param name="serviceBinder">Service methods will be bound by calling <c>AddMethod</c> on this object.</param>
+    /// <param name="serviceImpl">An object implementing the server-side handling logic.</param>
+    [global::System.CodeDom.Compiler.GeneratedCode("grpc_csharp_plugin", null)]
+    public static void BindService(grpc::ServiceBinderBase serviceBinder, SiteStreamServiceBase serviceImpl)
+    {
+      serviceBinder.AddMethod(__Method_SubscribeInstance, serviceImpl == null ? null : new grpc::ServerStreamingServerMethod<global::ScadaLink.Communication.Grpc.InstanceStreamRequest, global::ScadaLink.Communication.Grpc.SiteStreamEvent>(serviceImpl.SubscribeInstance));
+    }
+
+  }
+}
+#endregion