Thread safety in Swift
I think Alexander W has the right idea, but I would advise synchronizing on self as a general rule. Perhaps the suggestion I posted here may help:
You can implement your Getters Setters on thread-safe properties with use of dispatch_semaphore_t, NSLock or pthread_mutex_t, or similiar stuff.
Currently, there are no attributes, which define some behaviour, like atomic/nonatomic quialifers of Obj-C