nsIFeedProgressListener in Firefox 3.0

 Called after each entry/item. If the document is a standalone
 item or entry, this HandleFeedAtFirstEntry will not have been
 called. Also, this entry's parent field will be null.
 
 @param entry
        An object implementing nsIFeedEntry that represents the latest
        entry encountered.
 @param result
        An object implementing nsIFeedResult representing the feed 
        and its metadata. 

 Called when the first entry/item is encountered. In Atom, all
 feed data is required to preceed the entries. In RSS, the data
 usually does. If the type is one of the entry/item-only types,
 this event will not be called.

 @param result
        An object implementing nsIFeedResult representing the feed 
        and its metadata. At this point, the result will likely have
        most of its feed-level metadata.

 StartFeed will be called as soon as a reasonable start to
 a feed is detected. 
  
 @param result
        An object implementing nsIFeedResult representing the feed 
        and its metadata. At this point, the result has version 
        information.

 ReportError will be called in the event of fatal
 XML errors, or if the document is not a feed. The bozo 
 bit will be set if the error was due to a fatal error. 
 
 @param errorText
        A short description of the error.
 @param lineNumber
        The line on which the error occured.