Posting NSNotification on the main thread

Question

I found the following code snippet which allows NSNotification to be posted on the main thread from any background thread. I would like to know if this is a saf

Answer 1

YES

Swift 2 syntax

dispatch_async(dispatch_get_main_queue()) {
    NSNotificationCenter.defaultCenter().postNotificationName("updateSpinner", object: nil, userInfo: ["percent":15])
}

Swift 3 syntax

DispatchQueue.main.async {
    NotificationCenter.default.post(name: "updateSpinner", object: nil, userInfo: ["percent":15])
}