Comment 1 for bug 374740

Just as a comment, the new code path grabs a StreamSource and a StreamSink, and then passes the stream from source into sink. The code handling this is bzrlib.fetch.RepoFetcher. Both Source and Sink could be local, or could be remote, only the RepoFetcher is known to be the local client. It never sees individual records, but perhaps it could get callbacks somehow, so that it can update progress info.