Write runnable, runtime emitted assemblies to disk with .NET 9

Program.cs

using System;
using System.IO;
using System.Reflection;
using System.Reflection.Emit;
using System.Reflection.Metadata;
using System.Reflection.Metadata.Ecma335;
using System.Reflection.PortableExecutable;

var assemblyPath = "test.dll";
//CreateAndSaveAssembly(assemblyPath);
UseAssembly(assemblyPath);
;

static void CreateAndSaveAssembly(string assemblyPath)
{
	PersistedAssemblyBuilder ab = new PersistedAssemblyBuilder(
		new AssemblyName("MyAssembly"),
		typeof(object).Assembly
	);
	TypeBuilder tb = ab.DefineDynamicModule("MyModule")
		.DefineType("MyType", TypeAttributes.Public | TypeAttributes.Class);

	MethodBuilder entryPoint = tb.DefineMethod(
		"Main",
		MethodAttributes.HideBySig | MethodAttributes.Public | MethodAttributes.Static
	);
	ILGenerator il = entryPoint.GetILGenerator();
	// ...
	il.EmitWriteLine("Hello World!");
	il.Emit(OpCodes.Ret);
	
	tb.CreateType();

	MetadataBuilder metadataBuilder = ab.GenerateMetadata(
		out BlobBuilder ilStream,
		out BlobBuilder fieldData
	);
	PEHeaderBuilder peHeaderBuilder = new PEHeaderBuilder(
		imageCharacteristics: Characteristics.ExecutableImage);

	ManagedPEBuilder peBuilder = new ManagedPEBuilder(
		header: peHeaderBuilder,
		metadataRootBuilder: new MetadataRootBuilder(metadataBuilder),
		ilStream: ilStream,
		mappedFieldData: fieldData,
		entryPoint: MetadataTokens.MethodDefinitionHandle(entryPoint.MetadataToken)
	);

	BlobBuilder peBlob = new BlobBuilder();
	peBuilder.Serialize(peBlob);

	using var fileStream = new FileStream(assemblyPath, FileMode.Create, FileAccess.Write);
	peBlob.WriteContentTo(fileStream);
}

static void UseAssembly(string assemblyPath)
{
	Assembly assembly = Assembly.LoadFrom(assemblyPath);
	var type = assembly.GetType("MyType") ?? throw new("no type found");
	MethodInfo? method = type?.GetMethod("Main") ?? throw new("no method found");
	Console.WriteLine(method?.Invoke(null, null));
}