title: Value of type 'DispatchQueue' has no member 'asynchronously' - Swift 3
body: <p>I just updated my xcode8 to Swift 3 and I received this error:</p>
  
  <pre><code>Value of type 'DispatchQueue' has no member 'asynchronously'
  </code></pre>
  
  <p>on this line:</p>
  
  <pre><code>   DispatchQueue.main.asynchronously(execute:
  </code></pre>
  
  <p>Here's the entire snippet:</p>
  
  <pre><code>  DispatchQueue.main.asynchronously(execute: {
  
                          //Display alert message with confirmation
                          let myAlert = UIAlertController(title: "Alert", message:messageToDisplay, preferredStyle: UIAlertControllerStyle.Alert);
  
  
  
  
                          let okAction = UIAlertAction(title:"OK", style:UIAlertActionStyle.Default){
  
                              action in self.dismissViewControllerAnimated(true, completion:nil);
  
                          }
  
                          myAlert.addAction(okAction)
                          self.presentViewController(myAlert, animated:true, completion:nil);
                      });
                  }
              }
              catch let error as NSError {
                  print(error.localizedDescription)
              }
  
          }
  
          task.resume()
  
  }
  }
  </code></pre>
  
  <p>Recently updating to Swift 3 has given me a lot of errors, they automatically fixed but this one will not fix on its own and I do not know what to do.</p>