title: How to set headers in http get request?
body: <p>I'm doing a simple http GET in Go:</p>
  
  <pre><code>client := &amp;http.Client{}
  req, _ := http.NewRequest("GET", url, nil)
  res, _ := client.Do(req)
  </code></pre>
  
  <p>But I can't found a way to customize the request header in the <a href="http://golang.org/pkg/net/http/" rel="noreferrer">doc</a>, thanks</p>