- Better progress guage handling of the situation where we have received
  more bytes than are in the torrent, but hash check failures mean
  we aren't actually as far along as we wish.  In other words, raw data
  rx vs. checksummed pieces.

- UDP tracker support (BEP 15).

- Multi-tracker support.

- Multiple torrents per unworkable process support, along with hooks
  to load new torrents etc in the control server.

- Encryption.

- DHT/Kadamalia overlay network support.

- Rate limiting.
