C# и WinAPI SendMessageTimeout()

using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
using System.ComponentModel;
using System.Threading;
 
namespace testCreateProcess
{
    class Program
    {
        [Flags]
        public enum SendMessageTimeoutFlags : uint
        {
            SMTO_NORMAL = 0x0,
            SMTO_BLOCK = 0x1,
            SMTO_ABORTIFHUNG = 0x2,
            SMTO_NOTIMEOUTIFNOTHUNG = 0x8,
            SMTO_ERRORONEXIT = 0x0020
        }
 
        [StructLayout(LayoutKind.Sequential)]
        public struct SECURITY_ATTRIBUTES
        {
            public int nLength;
            public IntPtr lpSecurityDescriptor;
            public int bInheritHandle;
        }
 
        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
        struct STARTUPINFO
        {
            public Int32 cb;
            public string lpReserved;
            public string lpDesktop;
            public string lpTitle;
            public Int32 dwX;
            public Int32 dwY;
            public Int32 dwXSize;
            public Int32 dwYSize;
            public Int32 dwXCountChars;
            public Int32 dwYCountChars;
            public Int32 dwFillAttribute;
            public Int32 dwFlags;
            public Int16 wShowWindow;
            public Int16 cbReserved2;
            public IntPtr lpReserved2;
            public IntPtr hStdInput;
            public IntPtr hStdOutput;
            public IntPtr hStdError;
        }
 
        [StructLayout(LayoutKind.Sequential)]
        internal struct PROCESS_INFORMATION
        {
            public IntPtr hProcess;
            public IntPtr hThread;
            public int dwProcessId;
            public int dwThreadId;
        }
 
        [DllImport("kernel32.dll")]
        static extern bool CreateProcess(string lpApplicationName,
          string lpCommandLine, ref SECURITY_ATTRIBUTES lpProcessAttributes,
          ref SECURITY_ATTRIBUTES lpThreadAttributes, bool bInheritHandles,
          uint dwCreationFlags, IntPtr lpEnvironment, string lpCurrentDirectory,
          [In] ref STARTUPINFO lpStartupInfo,
          out PROCESS_INFORMATION lpProcessInformation);
 
        [DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
        public static extern IntPtr SendMessageTimeout(
            IntPtr windowHandle,
            uint Msg,
            IntPtr wParam,
            IntPtr lParam,
            SendMessageTimeoutFlags flags,
            uint timeout,
            out IntPtr result);
 
        [DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
        static extern uint RegisterWindowMessage(string lpString);
 
        [DllImport("user32.dll", SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        static extern bool IsHungAppWindow(IntPtr hWnd);
 
        [DllImport("user32.dll")]
        [return: MarshalAs(UnmanagedType.Bool)]
        static extern bool IsWindow(IntPtr hWnd);
 
        static void Main(string[] args)
        {
            const uint NORMAL_PRIORITY_CLASS = 0x0020;
 
            SECURITY_ATTRIBUTES pSec = new SECURITY_ATTRIBUTES();
            SECURITY_ATTRIBUTES tSec = new SECURITY_ATTRIBUTES();
            pSec.nLength = Marshal.SizeOf(pSec);
            tSec.nLength = Marshal.SizeOf(tSec);
 
            STARTUPINFO sInfo = new STARTUPINFO();
            PROCESS_INFORMATION pInfo = new PROCESS_INFORMATION();
 
            bool result =
                CreateProcess(@"D:\hungtest.exe",
                    null,
                    ref pSec,
                    ref tSec,
                    false,
                    NORMAL_PRIORITY_CLASS,
                    IntPtr.Zero,
                    null,
                    ref sInfo,
                    out pInfo);
 
            var hWnd = pInfo.hThread;
 
            Thread.Sleep(1);
 
            Console.WriteLine("HANDLE: " + hWnd);
            Console.WriteLine("IsWindow(): " + IsWindow(hWnd));
            Console.ReadKey();
 
            while (true)
            {
                var mesg = RegisterWindowMessage("WM_NULL");
                IntPtr temp;
 
                var res = 
                    SendMessageTimeout(hWnd, mesg, IntPtr.Zero, IntPtr.Zero,
                    SendMessageTimeoutFlags.SMTO_ABORTIFHUNG | SendMessageTimeoutFlags.SMTO_BLOCK, 500, out temp);
 
                Console.WriteLine(res);
 
                Thread.Sleep(5000);
            }
        }
    }
}