title: What is the difference between URLRequest and URL?
body: <p>I am using <code>URLSession</code> to download file. Two methods are there:</p>
  
  <pre><code>downloadTask(with request: URLRequest)
  </code></pre>
  
  <p>and</p>
  
  <pre><code>downloadTask(with url: URL).
  </code></pre>
  
  <p>What is difference between the two? Apart from POST, PUT, is there any special use for simple download?</p>