Sample plugin cleanup (#3857)

packages/http-client-csharp/generator/Microsoft.Generator.CSharp/src/OutputLibrary.cs

@@ -57,6 +57,6 @@ namespace Microsoft.Generator.CSharp
         }
 
         // TODO - make this more additive instead of replace https://github.com/microsoft/typespec/issues/3827
-        protected internal virtual OutputLibraryVisitor[] GetOutputLibraryVisitors() => [];
+        protected internal virtual IEnumerable<OutputLibraryVisitor> GetOutputLibraryVisitors() => [];
     }
 }

packages/http-client-csharp/generator/SamplePlugin/src/OutputTypes/SamplePluginOutputLibrary.cs

@@ -1,12 +1,12 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License.
 
-using Microsoft.Generator.CSharp;
+using System.Collections.Generic;
 using Microsoft.Generator.CSharp.ClientModel;
 namespace SamplePlugin
 {
     public class SamplePluginOutputLibrary : ScmOutputLibrary
     {
-        protected override OutputLibraryVisitor[] GetOutputLibraryVisitors() => [new SamplePluginOutputLibraryVisitor()];
+        protected override IEnumerable<SamplePluginOutputLibraryVisitor> GetOutputLibraryVisitors() => [new SamplePluginOutputLibraryVisitor()];
     }
 }

packages/http-client-csharp/generator/SamplePlugin/src/SampleCodeModelPlugin.cs

@@ -1,39 +1,19 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License.
 
-using System;
-using System.ClientModel;
-using System.Collections.Generic;
 using System.ComponentModel.Composition;
-using Microsoft.CodeAnalysis;
 using Microsoft.Generator.CSharp;
 using Microsoft.Generator.CSharp.ClientModel;
-using Microsoft.Generator.CSharp.Primitives;
-using Microsoft.Generator.CSharp.Providers;
 
 namespace SamplePlugin
 {
     [Export(typeof(CodeModelPlugin))]
     [ExportMetadata("PluginName", nameof(SampleCodeModelPlugin))]
-    public class SampleCodeModelPlugin : ClientModelPlugin
+    [method: ImportingConstructor]
+    public class SampleCodeModelPlugin(GeneratorContext context) : ClientModelPlugin(context)
     {
-        private static SampleCodeModelPlugin? _instance;
-        internal static SampleCodeModelPlugin Instance => _instance ?? throw new InvalidOperationException("SampleCodeModelPlugin is not loaded.");
-
-        public override TypeProviderWriter GetWriter(TypeProvider provider) => new(provider);
-
-        public override SamplePluginTypeFactory TypeFactory { get; }
-
-        public override IReadOnlyList<MetadataReference> AdditionalMetadataReferences => [MetadataReference.CreateFromFile(typeof(ClientResult).Assembly.Location)];
+        public override SamplePluginTypeFactory TypeFactory { get; } = new SamplePluginTypeFactory();
 
         public override OutputLibrary OutputLibrary { get; } = new SamplePluginOutputLibrary();
-
-        [ImportingConstructor]
-        public SampleCodeModelPlugin(GeneratorContext context)
-            : base(context)
-        {
-            TypeFactory = new SamplePluginTypeFactory();
-            _instance = this;
-        }
     }
 }