/**
     * Called from {@link start_display()}.
     * 
     * @param DATE_TIME $time_modified
     * @param NEWSFEED_RENDERER_OPTIONS $options
     * @access private
     * @abstract
     */
    protected function _start_display($time_modified, $options)
    {
        parent::_start_display($time_modified, $options);
        ?>
<rss version="2.0">
  <channel>
    <docs>http://www.rssboard.org/rss-specification</docs>
    <generator><?php 
        echo $this->_as_xml($this->generator);
        ?>
</generator>
    <language><?php 
        echo $this->_as_xml($this->language);
        ?>
</language>
    <ttl><?php 
        echo $this->_as_xml($this->ttl_in_minutes);
        ?>
</ttl>
    <title><![CDATA[<?php 
        $this->title->display();
        ?>
]]></title>
    <link><?php 
        echo $this->_as_xml($this->base_url);
        ?>
</link>
    <pubDate><?php 
        echo $time_modified->as_RFC_2822();
        ?>
</pubDate>
    <lastBuildDate><?php 
        echo $time_modified->as_RFC_2822();
        ?>
</lastBuildDate>
    <image>
      <link><?php 
        echo $this->_as_xml($this->base_url);
        ?>
</link>
      <title><![CDATA[<?php 
        $this->title->display();
        ?>
]]></title>
      <url><?php 
        echo $this->context->get_icon_url($this->icon_file, One_hundred_px);
        ?>
</url>
    </image>
    <description><![CDATA[<?php 
        echo $this->_as_xml($this->description);
        ?>
]]></description>
    <copyright><![CDATA[<?php 
        echo $this->_as_xml($this->copyright);
        ?>
]]></copyright>
<?php 
    }
    /**
     * Called from {@link start_display()}.
     * 
     * @param DATE_TIME $time_modified
     * @param NEWSFEED_RENDERER_OPTIONS $options
     * @access private
     * @abstract
     */
    protected function _start_display($time_modified, $options)
    {
        parent::_start_display($time_modified, $options);
        $html = isset($options) && $options->handler_type == Handler_html_renderer;
        ?>
<feed xmlns="http://www.w3.org/2005/Atom">
  <generator uri="<?php 
        echo $this->base_url;
        ?>
" version="<?php 
        echo $this->context->version;
        ?>
">
    <?php 
        echo $this->_as_xml($this->generator);
        ?>

  </generator>
  <?php 
        _echo_atom_text_tag('title', $this->title->as_text(), $this->language, $html);
        ?>
  <id><?php 
        echo $this->_as_xml($this->base_url);
        ?>
</id>
  <link rel="self" href="<?php 
        echo $this->_as_xml($this->env->url(Url_part_all));
        ?>
"/>
  <updated><?php 
        echo $time_modified->as_RFC_3339();
        ?>
</updated>
  <icon><?php 
        echo $this->context->get_icon_url($this->icon_file, One_hundred_px);
        ?>
</icon>
  <?php 
        _echo_atom_text_tag('subtitle', $this->description, $this->language, $html);
        ?>
  <?php 
        _echo_atom_text_tag('rights', $this->copyright, $this->language, $html);
    }