--follow-torrent=true|false|mem If true or mem is specified, when a file
whose suffix is .torrent or content type is
application/x-bittorrent is downloaded, aria2
parses it as a torrent file and downloads files
mentioned in it.
If mem is specified, a torrent file is not
written to the disk, but is just kept in memory.
If false is specified, the .torrent file is
downloaded to the disk, but is not parsed as a
torrent and its contents are not downloaded.