This will define a new method on `Object` which we shouldn't do.  I know the current facts define both `metadata` and `userdata` in this manner, but they definitely should not and are a really bad example.

Please put this method in a module or a class so that we don't pollute `Object`'s instance methods.  This is important because all objects in Ruby are a kind of Object, so all objects will then get this method.

-Jeff