现在很简单:

let serialQueue = DispatchQueue(label: "my serial queue")

默认值是serial，要获得concurrent，可以使用可选属性参数.concurrent

你可以在swift 3.0中使用这段代码创建调度队列

DispatchQueue.main.async
 {
   /*Write your code here*/
 }

   /* or */

let delayTime = DispatchTime.now() + Double(Int64(0.5 * Double(NSEC_PER_SEC))) / Double(NSEC_PER_SEC)                   
DispatchQueue.main.asyncAfter(deadline: delayTime)
{
  /*Write your code here*/
}

 DispatchQueue.main.async {
          self.collectionView?.reloadData() // Depends if you were populating a collection view or table view
    }


OperationQueue.main.addOperation {
    self.lblGenre.text = self.movGenre
}

//使用操作队列如果你需要填充对象(标签，imageview, textview)在你的视图控制器

Swift 3

   DispatchQueue.main.async {
        // Write your code here
    }

DispatchQueue.main.async(execute: {
   // code
})

 let newQueue = DispatchQueue(label: "newname")
 newQueue.sync { 

 // your code

 }