Constant DOWNLOAD_CONCURRENT_THRESHOLD 

pub const DOWNLOAD_CONCURRENT_THRESHOLD: usize = _; // 10_485_760usize

Routing threshold for downloads: below this, Client::download uses a plain single-connection stream; at or above it, downloads go through the concurrent/pipelined engine (Y worker connections, each X requests deep). Independent of BIG_FILE_THRESHOLD on purpose - that constant is upload’s protocol-mandated saveBigFilePart boundary, and reusing it here was coincidental, not protocol-driven. Same value today, but free to diverge since nothing in the download path actually depends on it matching the upload number.