Downloading files is very slow

[kingalg]

Version: 2.0.1-alpha.0

Downloading files is working but it's really slow.

Example - it's taking more than 2 hours to download 62mb file.

[holmesworcester]

The history on this is that when we increased concurrency we saw large downloads would often or always fail. But when we decrease concurrency to 1, downloads are slow. We should look into this again after upgrading ipfs/libp2p.

Another factor is that we had to write our own logic for downloading and retrying blocks, because the standard IPFS downloader would fail when downloading over Tor, perhaps due to increased latency or the higher risk of timeouts.