stopSync = async () => {
    if (started) {
      started = false
      await queue.clear()
      pubsub.removeEventListener('subscription-change', handlePeerSubscribed)
      pubsub.removeEventListener('message', handleUpdateMessage)
      await libp2p.unhandle(headsSyncAddress)
      await pubsub.unsubscribe(address)
      libp2p.removeEventListener('peer:disconnect', handlePeerDisconnected)
      peers.clear()
    }
  }
Stop the Sync Protocol.
@function stop
@memberof module:Sync~Sync
@instance