code: func (s *LightEthereum) Start(srvr *p2p.Server) error {
  	log.Warn("Light client mode is an experimental feature")
  	s.startBloomHandlers(params.BloomBitsBlocksClient)
  	s.netRPCService = ethapi.NewPublicNetAPI(srvr, s.networkId)
  	// clients are searching for the first advertised protocol in the list
  	protocolVersion := AdvertiseProtocolVersions[0]
  	s.serverPool.start(srvr, lesTopic(s.blockchain.Genesis().Hash(), protocolVersion))
  	s.protocolManager.Start(s.config.LightPeers)
  	return nil
  }
docs: // Start implements node.Service, starting all internal goroutines needed by the
  // Ethereum protocol implementation.