Size of the Managed Object

I was trying to get the managed size of the objects, but was stuck. Then after searching, i found this blog of Chris Brumme. He says that "We don't expose the managed size of objects because we want to reserve the ability to change the way we lay these things out".  Got another interesting post from the same post. Its from Sam Gentile's Blog. He Says that we can get the size of the Managed Value Types and not Managed Reference Types. Haven't tried myself, but sounds interesting!!