Forward metadata record values as headers in the warc splitter
Improve the Warc splitter part of the camel component in order to associate with response records the values of the metadata records.
For instance, Heritrix is able to add the source (i.e. seed) of a page, but this is in the metadata, not in the response record.
The two records are linked (according to WARC specification) by the WARC-Record-Id and WARC-Refers-To headers, thus it should be easy to do.
Moreover, metadata record are always shipped with their associated record.