From 7b3070768187e41d9420a14a77a0513209999383 Mon Sep 17 00:00:00 2001
From: Roger Kratz <roger.kratz@gmail.com>
Date: Wed, 17 Feb 2021 13:48:23 +0100
Subject: [PATCH] A benchmark showing issue #1252

---
 bench/Autofac.Benchmarks/Benchmarks.cs        |  3 +-
 .../OnActivatedBenchmark.cs                   | 36 +++++++++++++++++++
 2 files changed, 38 insertions(+), 1 deletion(-)
 create mode 100644 bench/Autofac.Benchmarks/OnActivatedBenchmark.cs

diff --git a/bench/Autofac.Benchmarks/Benchmarks.cs b/bench/Autofac.Benchmarks/Benchmarks.cs
index f777b71f8..2b932ca7a 100644
--- a/bench/Autofac.Benchmarks/Benchmarks.cs
+++ b/bench/Autofac.Benchmarks/Benchmarks.cs
@@ -28,7 +28,8 @@ public static class Benchmarks
             typeof(PropertyInjectionBenchmark),
             typeof(RootContainerResolveBenchmark),
             typeof(OpenGenericBenchmark),
-            typeof(MultiConstructorBenchmark)
+            typeof(MultiConstructorBenchmark),
+            typeof(OnActivatedBenchmark)
         };
     }
 }
diff --git a/bench/Autofac.Benchmarks/OnActivatedBenchmark.cs b/bench/Autofac.Benchmarks/OnActivatedBenchmark.cs
new file mode 100644
index 000000000..95b595f8e
--- /dev/null
+++ b/bench/Autofac.Benchmarks/OnActivatedBenchmark.cs
@@ -0,0 +1,36 @@
+using System;
+using System.Collections.Generic;
+using BenchmarkDotNet.Attributes;
+
+namespace Autofac.Benchmarks
+{
+    public class OnActivatedBenchmark
+    {
+        [Benchmark]
+        public void ResolveWithOnActivatedWithAction()
+        {
+            var builder = new ContainerBuilder();
+            Action<ContainerBuilder> someAction;
+            builder
+                .RegisterType<FakeService>()
+                .OnActivated(c =>
+                {
+                    someAction = b =>
+                    {
+                        b.RegisterInstance(c.Instance);
+                    };
+                });
+            using var container = builder.Build();
+            container.Resolve<FakeService>();
+        }
+
+        internal class FakeService
+        {
+            private IEnumerable<int> _data;
+            public FakeService()
+            {
+                _data = new int[1000];
+            }
+        }
+    }
+}