title: Check if boolean value is set in Go
body: <p>Is it possible to differentiate between <code>false</code> and an unset boolean value in go? </p>
  
  <p>For instance, if I had this code</p>
  
  <pre><code>type Test struct {
      Set bool
      Unset bool
  }
  
  test := Test{ Set: false }
  </code></pre>
  
  <p>Is there any difference between <code>test.Set</code> and <code>test.Unset</code> and if so how can I tell them apart? </p>