A file to be used for caching the incoming RSS feed.
Each time the RSS adapter downloads the FeedURL, it will cache the contents of the RSS feed as a list of hashes of each item in CacheFile. CachePeriod controls the length of time these items are cached. At the beginning of each download, the adapter will remove all expired cache entries from the cache file.
Note: the default cache period is 7 days. To disable caching, set CachePeriod to 0.
This property is not available in the Sender.