title: Golang transform http.Header into array
body: <p>I'm sending POST request:</p>
  
  <pre><code>req, err := http.NewRequest("POST", link, bytes.NewBuffer(jsonStr))
  client := &amp;http.Client{Timeout: tm}
  resp, err := client.Do(req)
  </code></pre>
  
  <p>I receive <code>resp.Header</code> in format with type <code>http.Header</code></p>
  
  <p>I need to something like this:</p>
  
  <pre><code>[
      "Server: nginx/1.4.4",
      "Date: Wed, 24 Feb 2016 19:09:49 GMT"
  ]
  </code></pre>
  
  <p>I don't know how to approach this problem, because I don't know how to deal with <code>http.Header</code> datatype. Could someone help please</p>