Changing UILabel text has delay, but why?

Question

in my app I want to set the text of an UILabel. The text comes from a JSON-object. I add my UILabel to my storyboard, set the IBOutlet and

Answer 1

c_rath's answer is correct. In swift 3 the syntax was changed (yet again) to

DispatchQueue.main.async {
    self. label_news?.text = resp.NewsText
}