Reverting "unused" wrapper that was deleted. Apparently it's not as "…

…unused" as it seems...

src/Agent/NewRelic/Agent/Core/Utilities/ExtensionsLoader.cs

@@ -38,6 +38,7 @@ public static void Initialize(string installPathExtensionsDirectory)
                 { "NewRelic.Providers.Wrapper.AspNetCore.InvokeActionMethodAsync",                                  Path.Combine(_installPathExtensionsDirectory, "NewRelic.Providers.Wrapper.AspNetCore.dll") },
 
                 { "GenericHostWebHostBuilderExtensionsWrapper6Plus",                                                Path.Combine(_installPathExtensionsDirectory, "NewRelic.Providers.Wrapper.AspNetCore6Plus.dll") },
+                { "BuildCommonServicesWrapper6Plus",                                                                Path.Combine(_installPathExtensionsDirectory, "NewRelic.Providers.Wrapper.AspNetCore6Plus.dll") },
                 { "InvokeActionMethodAsyncWrapper6Plus",                                                            Path.Combine(_installPathExtensionsDirectory, "NewRelic.Providers.Wrapper.AspNetCore6Plus.dll") },
                 { "ResponseCompressionBodyOnWriteWrapper",                                                          Path.Combine(_installPathExtensionsDirectory, "NewRelic.Providers.Wrapper.AspNetCore6Plus.dll") },
 

src/Agent/NewRelic/Agent/Extensions/Providers/Wrapper/AspNetCore6Plus/BuildCommonServicesWrapper6Plus.cs

@@ -0,0 +1,42 @@
+// Copyright 2020 New Relic, Inc. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+using System.Linq;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.Extensions.DependencyInjection;
+using NewRelic.Agent.Api;
+using NewRelic.Agent.Extensions.Providers.Wrapper;
+
+namespace NewRelic.Providers.Wrapper.AspNetCore6Plus
+{
+    public class BuildCommonServicesWrapper6Plus : IWrapper
+    {
+        public bool IsTransactionRequired => false;
+
+        public CanWrapResponse CanWrap(InstrumentedMethodInfo methodInfo)
+        {
+            return new CanWrapResponse(nameof(BuildCommonServicesWrapper6Plus).Equals(methodInfo.RequestedWrapperName));
+        }
+
+        public AfterWrappedMethodDelegate BeforeWrappedMethod(InstrumentedMethodCall instrumentedMethodCall, IAgent agent, ITransaction transaction)
+        {
+            //Do nothing at start of method
+
+            return Delegates.GetDelegateFor<IServiceCollection>(onSuccess: HandleSuccess);
+
+            void HandleSuccess(IServiceCollection services)
+            {
+                //Forced evaluation is important. Do not remove ToList()
+                var startupFilters = services.Where(serviceDescriptor => serviceDescriptor.ServiceType == typeof(IStartupFilter)).ToList();
+
+                services.AddTransient<IStartupFilter>(provider => new AddNewRelicStartupFilter(agent));
+
+                foreach (var filter in startupFilters)
+                {
+                    services.Remove(filter); // Remove from early in pipeline
+                    services.Add(filter); // Add to end after our AddNewRelicStartupFilter
+                }
+            }
+        }
+    }
+}

src/Agent/NewRelic/Agent/Extensions/Providers/Wrapper/AspNetCore6Plus/Instrumentation.xml

@@ -10,6 +10,11 @@ SPDX-License-Identifier: Apache-2.0
         <exactMethodMatcher methodName="ConfigureWebHost" />
       </match>
     </tracerFactory>
+    <tracerFactory name="BuildCommonServicesWrapper6Plus">
+      <match assemblyName="Microsoft.AspNetCore.Hosting" className="Microsoft.AspNetCore.Hosting.WebHostBuilder"  minVersion="6.0.0.0">
+        <exactMethodMatcher methodName="BuildCommonServices" />
+      </match>
+    </tracerFactory>
     <tracerFactory name="InvokeActionMethodAsyncWrapper6Plus">
       <match assemblyName="Microsoft.AspNetCore.Mvc.Core" className="Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker" minVersion="6.0.0.0">
         <exactMethodMatcher methodName="InvokeActionMethodAsync" />