public static void TestMultipleSized4096CopyToAlloca(ref MultipleSized4096 a, ref Sized4096 b, ref Sized4096 c)
        {
            MultipleSized4096 d = default;

            d.a = b;
            b   = d.b;
            c   = a.a;
            a   = d;
        }
 public static void TestMultipleSized4096(ref MultipleSized4096 a, ref Sized4096 b)
 {
     a.a = b;
     a.a.First = 42;
     b         = a.b;
 }