FloodSub {.public.} = ref object of PubSub
  floodsub*: PeerTable
  seen*: TimedCache[MessageID]
  seenSalt*: seq[byte]

FloodSubCodec = "/floodsub/1.0.0"

proc addSeen(f: FloodSub; msgId: MessageID): bool {....raises: [Defect], tags: [].}

proc handleSubscribe(f: FloodSub; peer: PubSubPeer; topic: string;
                     subscribe: bool) {....raises: [Defect],
                                        tags: [WriteIOEffect, TimeEffect].}

proc hasSeen(f: FloodSub; msgId: MessageID): bool {....raises: [Defect], tags: [].}

method unsubscribePeer(f: FloodSub; peer: PeerId) {....raises: [Defect],
    tags: [RootEffect].}