message <span class="message">GetPrefArg</span>
{
  enum Mode
  {
    <span class="comment">/** 
     * Get the current value of the pref.
     */</span>
    CURRENT = 1;
    <span class="comment">/** 
     * Get the default value of the pref (not necessarily the
     * used value).
     */</span>
    DEFAULT = 2;
  }

  required <span class="string">string</span> section = 1; 
  required <span class="string">string</span> key     = 2; 
  optional <span class="number">Mode  </span> mode    = 3; 
}
