* @param type
     * @return instance for type, null if the type cannot be unwrapped
     */
    <T extends Address> T unwrap ( Class<T> type );


    /**
     * 
     * @return the resolved host name, or the host address if it could not be resolved
     */
    String getHostName ();


    /**
     * Return the IP address as text such as "192.168.1.15".
     * 
     * @return the ip address
     */