Use source generation for the serializer

Author: lewing

eng/Versions.props

@@ -259,6 +259,6 @@
     <MicrosoftSymbolStoreVersion>1.0.406601</MicrosoftSymbolStoreVersion>
     <!-- installer version, for testing workloads -->
     <MicrosoftDotnetSdkInternalVersion>8.0.100-rtm.23506.1</MicrosoftDotnetSdkInternalVersion>
-    <SdkVersionForWorkloadTesting>$(MicrosoftDotnetSdkInternalVersion)</SdkVersionForWorkloadTesting>
+    <!-- <SdkVersionForWorkloadTesting>$(MicrosoftDotnetSdkInternalVersion)</SdkVersionForWorkloadTesting> -->
   </PropertyGroup>
 </Project>

src/mono/wasm/testassets/WasmBasicTestApp/LazyLoadingTest.cs

@@ -12,9 +12,12 @@ public static void Run()
     {
         // System.Text.Json is marked as lazy loaded in the csproj ("BlazorWebAssemblyLazyLoad"), this method can be called only after the assembly is lazy loaded
         // In the test case it is done in the JS before call to this method
-        var text = JsonSerializer.Serialize(new Person("John", "Doe"));
+        var text = JsonSerializer.Serialize(new Person("John", "Doe"), SourceGenerationContext.Default.Person);
         TestOutput.WriteLine(text);
     }
 
+    internal partial class SourceGenerationContext : JsonSerializerContext
+    {
+    }
     public record Person(string FirstName, string LastName);
 }