wuapi.ps1

$Source = @"
using System;
using System.Runtime.InteropServices;

namespace wuapi
{
    [ComImport, Guid("ef8208ea-2304-492d-9109-23813b0958e1"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
    public interface IUpdateInstaller4
    {
        void _VtblGap0_29(); // skip 4 (IDispatch) + 25 IUpdateInstaller4 methods

        [PreserveSig]
        int Commit(uint dwFlags);
    }

    public static class UpdateCommitter
    {
        public static int Commit(object comObject, uint dwFlags)
        {
            var updateInstaller = (IUpdateInstaller4)comObject;
            return updateInstaller.Commit(dwFlags);
        }
    }
}
"@
Add-Type -TypeDefinition $Source
$CommitResult=[wuapi.IUpdateInstaller4].InvokeMember('Commit',[Reflection.BindingFlags]::InvokeMethod, $null,  $UpdateInstaller, @(0))