switching dedup to use doc_id instead of stream_id, because we want to remove docs that have the same URL and near-identical content, timestamp is less important.
switching dedup to use doc_id instead of stream_id, because we want to remove docs that have the same URL and near-identical content,
timestamp is less important.

trec-kba/streamcorpus-pipeline,trec-kba/streamcorpus-pipeline,trec-kba/streamcorpus-pipeline