title: "DispatchQueue.main.async { [weak self] in" in Objective C?
body: <p>What is the equivalent of the Swift code:</p>
  
  <pre><code>DispatchQueue.main.async { [weak self] in
          self?.detectObjects()
      }
  </code></pre>
  
  <p>In Objective C?</p>
  
  <p>Thanks.</p>