Does the order of expression of an instance variable in Objective-C mean?

Question

I searched the web for tips on optimizing Objective-C code and came across this link. In this article, I saw a note below that I cannot understand.

Answer 1

This article is out of date. It was once true that ivars were stored in an Objective-C instance in the same way that structure members are stored, and thus memory alignment (slightly) affects access time.

, , ivars ( , Apple); ivar . , , .

, ivar .

Answer 2

ivars Objective-C, , . , , - , , .

; , C , .