This commit add a new DataError Variant for feeds that return 304.
Its expected behaviror and the current API of Source::into_feed
is kinda limiting the return type to make it easier to handle.
Up till now 304 was returning an Error to early return. Ideally
Source::into_feed will return a Multi variant Result Enum.
example:
enum FeedResult {
Ok(Success(feed)),
Ok(NotModified),
Err(err),
}
Hopefully in a refactor in the near Future™
Till then we will just have to match and ignore
DataError::FeedNotModified.
Additionally clear the Etags if the returned code is not 200 or 304.
Just to be extra safe. This is not as clean as it should, as this is
a temporary workaround until the API is reworked.
Related to #64
This is never used anywhere else apart from the testsuite. Instead
of ignoring etags we should instead not save them if the feed does
not return 200 or 304. See #64.
