Is it possible to set a field in a structure to be ignored by the
marshaler? I have a struct that needs to be self contained, but it
would require the use of fields extra fields to maintain it.

[StructLayout(LayoutKind.Sequential)]
public struct MyStruct
{
 public int size;
 public IntPtr ptr;

 // global fields that cannot be marshaled:
 private SomeOtherClass soc;
}

Is there a way to designate "soc" to be ignored, or to write a custom
marshaler that would do so? (i..e - 8 bytes would be marshaled, and
Marshal.Sizeof(soc) would return 8)