Rather than carrying around an Future in the IngestionEntry::Regular,
simply carry the plain B3Digest.
Code reading through a non-seekable data stream has no choice but to
read and upload blobs immediately, and code seeking through something
seekable (like a filesystem) probably knows better what concurrency to
pick when ingesting, rather than the consuming side.
(Our only) one of these seekable source implementations is now doing
exactly that. We produce a stream of futures, and then use
[StreamExt::buffered] to process more than one, concurrently.
We still keep the same order, to avoid shuffling things and violating
the stream order.
This also cleans up walk_path_for_ingestion in castore/import, as well
as ingest_dir_entries in glue/tvix_store_io.
Change-Id: I5eb70f3e1e372c74bcbfcf6b6e2653eba36e151d
Reviewed-on: https://cl.tvl.fyi/c/depot/+/11491
Autosubmit: flokli <flokli@flokli.de>
Reviewed-by: Connor Brewster <cbrewster@hey.com>
Tested-by: BuildkiteCI