code: func PullerConfigFromTopLevelConfig(systemChannel string, conf *localconfig.TopLevel, tlsKey, tlsCert []byte, signer crypto.LocalSigner) PullerConfig {
  	return PullerConfig{
  		Channel:             systemChannel,
  		MaxTotalBufferBytes: conf.General.Cluster.ReplicationBufferSize,
  		Timeout:             conf.General.Cluster.RPCTimeout,
  		TLSKey:              tlsKey,
  		TLSCert:             tlsCert,
  		Signer:              signer,
  	}
  }
docs: // PullerConfigFromTopLevelConfig creates a PullerConfig from a TopLevel config,
  // and from a signer and TLS key cert pair.
  // The PullerConfig's channel is initialized to be the system channel.