valueForKey:		method "foo", method "_foo"
			method "getFoo", method "_getFoo"
			ivar "_foo", ivar "foo"

takeValue:ForKey:	method "setFoo", method "_setFoo"
			ivar "foo", ivar "_foo"

storedValueForKey: 	method "_getFoo", method "_foo"
			ivar "_foo", ivar "foo"
			method "getFoo", method "foo"

takeStoredValueForKey:	method "_setFoo"
			ivar "_foo", ivar "foo"
			method "setFoo"