title: Getting annotation of enum value
body: <p>I know how to get an annotation of an enum value in Java.
  However Kotlin has its own reflection library and I feel there should be a better way to do the job.
  Could please anybody post an example.</p>
  
  <p>Just to be specific let's define an enum class</p>
  
  <pre class="lang-kotlin prettyprint-override"><code>enum class Enum {
      @SerialName("constant")
      Constant
  }
  </code></pre>
  
  <p>I need a function <code>f(e: Enum): String</code> so that <code>f(Enum.Constant) == "constant"</code>.</p>