What you'll build: BitTorrent protocol implementation with tracker support, peer wire protocol, piece management, and concurrent peer connections.

What you'll learn: P2P architecture, bencode parsing, TCP peer communication, managing 50+ concurrent connections, piece selection algorithms, SHA1 verification, tracker protocols (HTTP + UDP).

End state: Task 19 completed. BitTorrentProtocol implementation can download from .torrent files and magnet links, connect to trackers, exchange pieces with peers, and assemble the final file. DHT support is optional/deferred.