xx.csproj true 允许不安全代码和指针

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net5.0</TargetFramework>
    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
  </PropertyGroup>

  <PropertyGroup>
    <InvariantGlobalization>true</InvariantGlobalization>
  </PropertyGroup>

</Project>

Program.cs

#define RUNDISPOSE  // 注释预定义切换

using System;
using System.Runtime.InteropServices;

namespace Cmd
{
    class Program
    {
        static void Main(string[] args)
        {
            Test();
            GC.Collect();
            Console.WriteLine("Memory used after full collection:   {0:N0}", GC.GetTotalMemory(true));
            Console.WriteLine("Hello World!");
        }

        public static void Test()
        {
            
            unsafe
            {
                #if RUNDISPOSE
                using var _net = new NetworkChangeCleanup(int.MaxValue);
                #else 
                var _net = new NetworkChangeCleanup(int.MaxValue);
                #endif
                Console.WriteLine("size: {0}", Marshal.SizeOf<NetworkChangeCleanup>(_net));
                Console.WriteLine("object is {0}.", _net._handler.ToString());
            }

            

        }
    }

    [StructLayout(LayoutKind.Sequential)]
    sealed class NetworkChangeCleanup : IDisposable
    {
        public int _handler;

        public NetworkChangeCleanup(int handler)
        {
            _handler = handler;
        }

        // If user never disposes the HttpClient, use finalizer to remove from NetworkChange.NetworkAddressChanged.
        // _handler will be rooted in NetworkChange, so should be safe to use here.
        ~NetworkChangeCleanup() => Console.WriteLine("Finalized.");

        public void Dispose()
        {
            _handler = 0;
            Console.WriteLine("disposed.");

            #if RUNDISPOSE

            GC.SuppressFinalize(this); // 试试注释该方法

            #endif
        }
    }
}

C# 内存释放 IDisposable 与 析构方法的 关系