static extern void TestUnmanaged4([In, Out] ref SRKH k, [In, Out] ref Guid g);
static extern void TestUnmanaged2([In] ref SRKH k, [In] ref Guid g);
static extern void TestUnmanaged3(out SRKH k, out Guid g);
static extern void TestUnmanaged1(ref SRKH k, ref Guid g);