PInvoke SafeHandle via interface

custommarshaler.cs

using System;
using System.Runtime.InteropServices;
using FILETIME=System.Runtime.InteropServices.ComTypes.FILETIME;

namespace ConsoleApp4
{
	interface ISafeProcessHandle
	{
	}

	class SafeProcessHandle : SafeHandle, ISafeProcessHandle
	{
		public SafeProcessHandle(IntPtr invalidHandleValue, bool ownsHandle) : base(invalidHandleValue, ownsHandle)
		{
		}

		protected override bool ReleaseHandle()
		{
			return true;
		}

		public override bool IsInvalid => false;
	}

	class CustomSafeHandleMarshaler : ICustomMarshaler
	{
		public static ICustomMarshaler GetInstance(string type)
		{
			return new CustomSafeHandleMarshaler();
		}

		public object MarshalNativeToManaged(IntPtr pNativeData)
		{
			return new SafeProcessHandle(pNativeData,true);
		}

		public IntPtr MarshalManagedToNative(object ManagedObj)
		{
			return ((SafeProcessHandle)ManagedObj).DangerousGetHandle();
		}

		public void CleanUpNativeData(IntPtr pNativeData)
		{

		}

		public void CleanUpManagedData(object ManagedObj)
		{

		}

		public int GetNativeDataSize()
		{
			return IntPtr.Size;
		}
	}


	class Program
	{


		[DllImport("kernel32.dll", SetLastError = true, EntryPoint = "GetProcessTimes")]
		[return: MarshalAs(UnmanagedType.Bool)]
		static extern bool GetProcessTimesViaInterface(
			[MarshalAs(UnmanagedType.CustomMarshaler, MarshalTypeRef = typeof(CustomSafeHandleMarshaler))]
			ISafeProcessHandle hProcess,
			out FILETIME lpCreationTime,
			out FILETIME lpExitTime,
			out FILETIME lpKernelTime,
			out FILETIME lpUserTime);

		[DllImport("kernel32.dll", SetLastError = true)]
		[return: MarshalAs(UnmanagedType.Bool)]
		static extern bool GetProcessTimes(
			SafeHandle hProcess,
			out FILETIME lpCreationTime,
			out FILETIME lpExitTime,
			out FILETIME lpKernelTime,
			out FILETIME lpUserTime);

		static void Main(string[] args)
		{
			var p = new SafeProcessHandle(new IntPtr(-1), true);

			GetProcessTimesViaInterface(p, out var c, out var e, out var k, out var u);
			Console.WriteLine(u.dwLowDateTime);

			GetProcessTimes(p, out c, out e, out k, out u);
			Console.WriteLine(u.dwLowDateTime);
		}
	}
}