title: What is the meaning of keyword "throws" in Swift?
body: <p>What is meaning of "throws" keyword here:</p>
  
  <p><img src="https://i.stack.imgur.com/MIsg4.png" alt=""></p>
  
  <p>This code take so long to be executed and i think "throws" keyword in the image above related:</p>
  
  <pre><code>let url = URL(string:"\(APIs.postsImages)\(postImg)")
  let imgData = try? Data.init(contentsOf: url)
  self.postImage.image = UIImage.init(data: imgData)
  </code></pre>