Retrieves a views field value from the style plugin.
$index: The index count of the row as expected by views_plugin_style::get_field().
$field_id: The ID assigned to the required field in the display.
modules/ views/ plugins/ views_plugin_row_rss_fields.inc, line 173
- Contains an implementation of RSS items based on fields on a row plugin.
- Renders an RSS item based on fields.