In Objective-C, you could declare a property to be either atomic or nonatomic, being atomic the default value. In Swift, those keywords have disappeared and I didn't find any information regarding that in the Swift Programming Language guide, so I'm not sure if properties in Swift keep being atomic by default or not, or if there is another new way to define atomic or nonatomic.
I've read in this post that now by default properties are nonatomic, but no source provided.
