using System.Windows;

namespace ReproduceFinalizerMemoryLeak
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            do
            {
                Item item = new Item();
            } while (true);

            InitializeComponent();
        }
    }

    public class Item
    {
        private byte[] _bytes;

        public Item()
        {
            _bytes = new byte[10000];
        }

        ~Item()
        {

        }
    }
}

 ~Item()
        {
            using (System.IO.StreamWriter file =    new System.IO.StreamWriter(System.IO.Path.Combine(System.IO.Directory.GetCurrentDirectory(), @"WriteLines.txt"), true))
            {
                file.WriteLine("Item's finalizer is called.");
            }
            Console.WriteLine("Item's finalizer is called.");
        }

do
            {
                Item item = new Item();
                GC.Collect();
                GC.WaitForPendingFinalizers();
            } while (true);

 _bytes = new byte[10000]

 _bytes = new byte[100000]

do
            {
                Item item = new Item();
                GC.Collect();
                GC.WaitForPendingFinalizers();
               
            } while (true);

~Item()
{
}

_>Тем не менее в спецификации C# деструкторы есть : https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/language-specification/classes#destructors

Execution of the destructor for the instance may occur at any time after the instance becomes eligible for destruction.
When an instance is destructed, the destructors in that instance's inheritance chain are called, in order, from most derived to least derived.
A destructor may be executed on any thread.

Finalizers (which are also called destructors)

Неуправляемые ресурсы
Финализатор
IDisposable.Dispose

public void Dispose()
    {
        this.CloseHandle();
        GC.SuppressFinalize(this);//Это гарантирует, что финализатор объекта вызываться не будет.
    }

public abstract class SafeHandle : System.Runtime.ConstrainedExecution.CriticalFinalizerObject, IDisposable
{
...
~SafeHandle ();
}

class Unmanaged
{
    public static SafeHandle OpenResource(string resourceName);
}

class ResourceHolder : IDisposable
{
    SafeHandle _rsrcHandle;

    public ResourceHolder()
    {
        _rsrcHandle = Unmanaged.OpenResource();

        //вызов какого-то метода, который может бросить exception
        throw new SomeException();
    }

    public void Dispose()
    {
        _rsrcHandle.Dispose();
    }
}

...
using (var r = new ResourceHolder())
{
}
//Dispose вызван не будет, но остается надежда на вызов Finalize (~SafeHandle).

class Unmanaged
{
    public static SafeHandle OpenResource(string resourceName);
}

class ResourceHolder : IDisposable
{
    SafeHandle _rsrcHandle;

    public ResourceHolder()
    {
    bool initialized = false;
    try
    {
        _rsrcHandle = Unmanaged.OpenResource();
    
        //вызов какого-то метода, который может бросить exception

         initialized = true;
    }
    finally
    {
        if (!initialized) 
            _rsrcHandle.Dispose();
    }
    }

    public void Dispose()
    {
        _rsrcHandle.Dispose();
    }
}

...
using (var r = new ResourceHolder())
{
}

class Unmanaged
{
    public static SafeHandle OpenResource(string resourceName);
}

class ResourceHolder : IDisposable
{
    SafeHandle _rsrcHandle;

    public ResourceHolder()
    {
    }

    public Initialize()
    {
        _rsrcHandle = Unmanaged.OpenResource();
    }

    public void Dispose()
    {
        _rsrcHandle.Dispose();
    }
}

...
using (var r = new ResourceHolder())
{
    r.Initialize();
}

class Unmanaged
{
    public static SafeHandle OpenResource(string resourceName);
}

class ResourceHolder : IDisposable
{
    SafeHandle _rsrcHandle;
    SafeHandle _rsrcHandle1;
    SafeHandle _rsrcHandle2;
    SafeHandle _rsrcHandle3;
    SafeHandle _rsrcHandle4;
    SafeHandle _rsrcHandle5;

    public ResourceHolder()
    {
        bool initialized = false;
        try
        {
            _rsrcHandle = Unmanaged.OpenResource();
            _rsrcHandle1 = Unmanaged.OpenResource();
            _rsrcHandle2 = Unmanaged.OpenResource();
            _rsrcHandle3 = Unmanaged.OpenResource();
            _rsrcHandle4 = Unmanaged.OpenResource();
            _rsrcHandle5 = Unmanaged.OpenResource();
    
            //вызов какого-то метода, который может бросить exception

            initialized = true;
        }
        finally
        {
            if (!initialized)
                Dispose();
        }
    }

    public void Dispose()
    {
            _rsrcHandle?.Dispose();
            _rsrcHandle1?.Dispose();
            _rsrcHandle2?.Dispose();
            _rsrcHandle3?.Dispose();
            _rsrcHandle4?.Dispose();
            _rsrcHandle5?.Dispose();
    }
}

...
using (var r = new ResourceHolder())
{
}

 @implements IDisposable

public void Dispose()
{
    MessageService.Notify -= OnNotify;
}

var myFile = File.OpenWrite("C:\temp\0asdask12.txt");
Thread.Create(o=>myFile.Write(Encoding.UTF-8.GetBytes(o.ToString())).Start(myBigObject);

S>var myFile = File.OpenWrite("C:\temp\0asdask12.txt");
S>Thread.Create(o=>myFile.Write(Encoding.UTF-8.GetBytes(o.ToString())).Start(myBigObject);
S>

var myFile = File.OpenWrite("C:\temp\0asdask12.txt");
Thread.Create(o=>
{
    try     { myFile.Write(Encoding.UTF-8.GetBytes(o.ToString()); }
    finally { myFile.Dispose(); }
}).Start(myBigObject);