title: how to get return value in dispatch block?
body: <p>How can I get the return value from an asynchronous dispatch block?</p>
  
  <p>I came up with this example code:</p>
  
  <pre><code>if let url = URL(string: "https://google.com/") {
      let data: Data? = ***SOME_ASYNC_AWAIT_DISPATCH_GROUP&lt;T&gt;*** { return try? Data(contentsOf: url) }
      print("Downloaded Data: \(data)")
  }
  </code></pre>
  
  <p><strong>Goal:</strong> Here, I want the async call to produce a result and store it to the <code>data</code> constant so that I can use it.</p>