    def sync
      known = known_addresses.shuffle
      seen  = {}

      sync_seed = ->(seed) do
        server = Server.new seed

        unless seen[server.resolved_address]
          seen[server.resolved_address] = true

          hosts = sync_server(server)

          hosts.each do |host|
            sync_seed[host]
          end
        end
      end

      known.each do |seed|
        sync_seed[seed]
      end

      unless servers.empty?
        @dynamic_seeds = servers.map(&:address)
      end

      true
    end
The product receives input or data, but it does
        not validate or incorrectly validates that the input has the
        properties that are required to process the data safely and
        correctly.