Slimmer IOptions<T> (#49852)

* Slimmer IOptions<T>
- Use a Lazy instead of the IOptionsCache (which is a concurrent dictionary)

2 files changed, 23 insertions, 1 deletions

diff --git a/src/libraries/Microsoft.Extensions.Options/src/OptionsServiceCollectionExtensions.cs b/src/libraries/Microsoft.Extensions.Options/src/OptionsServiceCollectionExtensions.cs
index d9ff1e75b03..cfba9735907 100644
--- a/src/libraries/Microsoft.Extensions.Options/src/OptionsServiceCollectionExtensions.cs
+++ b/src/libraries/Microsoft.Extensions.Options/src/OptionsServiceCollectionExtensions.cs
@@ -26,7 +26,7 @@ namespace Microsoft.Extensions.DependencyInjection
                 throw new ArgumentNullException(nameof(services));
             }
 
-            services.TryAdd(ServiceDescriptor.Singleton(typeof(IOptions<>), typeof(OptionsManager<>)));
+            services.TryAdd(ServiceDescriptor.Singleton(typeof(IOptions<>), typeof(UnnamedOptionsManager<>)));
             services.TryAdd(ServiceDescriptor.Scoped(typeof(IOptionsSnapshot<>), typeof(OptionsManager<>)));
             services.TryAdd(ServiceDescriptor.Singleton(typeof(IOptionsMonitor<>), typeof(OptionsMonitor<>)));
             services.TryAdd(ServiceDescriptor.Transient(typeof(IOptionsFactory<>), typeof(OptionsFactory<>)));
diff --git a/src/libraries/Microsoft.Extensions.Options/src/UnnamedOptionsManager.cs b/src/libraries/Microsoft.Extensions.Options/src/UnnamedOptionsManager.cs
new file mode 100644
index 00000000000..6920efe506e
--- /dev/null
+++ b/src/libraries/Microsoft.Extensions.Options/src/UnnamedOptionsManager.cs
@@ -0,0 +1,22 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.Diagnostics.CodeAnalysis;
+
+namespace Microsoft.Extensions.Options
+{
+    internal class UnnamedOptionsManager<[DynamicallyAccessedMembers(Options.DynamicallyAccessedMembers)] TOptions> :
+        IOptions<TOptions>
+        where TOptions : class
+    {
+        private readonly Lazy<TOptions> _lazy;
+
+        public UnnamedOptionsManager(IOptionsFactory<TOptions> factory)
+        {
+            _lazy = new Lazy<TOptions>(() => factory.Create(Options.DefaultName));
+        }
+
+        public TOptions Value => _lazy.Value;
+    }
+}