TorrentBroadcastFactory is a BroadcastFactory of TorrentBroadcasts, i.e. BitTorrent-like broadcast variables.
initialize and stop do nothing.
unbroadcast removes all the persisted state associated with a TorrentBroadcast of a given ID.
newBroadcast[T: ClassTag](value_ : T, isLocal: Boolean, id: Long): Broadcast[T]
newBroadcast creates a TorrentBroadcast (for the input value_ and id and ignoring the isLocal parameter).