Fixing problem on Linux where dotnet run fails because we try to set an IIS config (#17903)

* Don't add a blanket rule to allow synchronous IO, should not be necessary for the new management API

* Add obsolete warning

* Catch errors while adding global rule to allow synchronous IO, which fails on non-windows machines

* Some updates based on PR feedback

Author: nul800sebastiaan

src/Umbraco.Web.Common/DependencyInjection/UmbracoBuilderExtensions.cs

@@ -1,6 +1,7 @@
 using System.Data.Common;
 using System.Net.Http.Headers;
 using System.Reflection;
+using System.Runtime.CompilerServices;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.DataProtection.Infrastructure;
 using Microsoft.AspNetCore.Hosting;
@@ -326,12 +327,40 @@ public static IUmbracoBuilder AddHelpers(this IUmbracoBuilder builder)
         return builder;
     }
 
-    [Obsolete("This is not necessary any more. This will be removed in v17")]
+    [Obsolete("This is not necessary any more. This will be removed in v16")]
     public static IUmbracoBuilder AddWebServer(this IUmbracoBuilder builder)
     {
+        builder.Services.Configure<KestrelServerOptions>(options =>
+        {
+            options.AllowSynchronousIO = true;
+        });
+
+        try
+        {
+            // See https://github.com/umbraco/Umbraco-CMS/pull/17886. This is a workaround for non-windows machines
+            // they won't have IIS available and trying to set this option will throw an exception.
+            //
+            // We're deferring this call to a method because if we just try to set the options here, we still get a
+            // TypeLoadException on non-windows machines.
+            // This workaround came from this comment: https://stackoverflow.com/a/3346975
+            AllowSynchronousIOForIIS(builder);
+        }
+        catch (TypeLoadException)
+        {
+            // Ignoring this exception because it's expected on non-windows machines
+        }
         return builder;
     }
 
+    // Prevents the compiler from inlining the method
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    private static void AllowSynchronousIOForIIS(IUmbracoBuilder builder) =>
+        builder.Services.Configure<IISServerOptions>(
+            options =>
+            {
+                options.AllowSynchronousIO = true;
+            });
+
     private static IProfiler GetWebProfiler(IConfiguration config, IHttpContextAccessor httpContextAccessor)
     {
         var isDebug = config.GetValue<bool>($"{Constants.Configuration.ConfigHosting}:Debug");