public BesuControllerBuilder fromEthNetworkConfig(
        final EthNetworkConfig ethNetworkConfig, final SyncMode syncMode) {
      return fromGenesisFile(ethNetworkConfig.genesisConfig(), syncMode)
          .networkId(ethNetworkConfig.networkId());
    }
From eth network config besu controller builder.

@param ethNetworkConfig the eth network config
@param syncMode The sync mode
@return the besu controller builder
app/src/main/java/org/hyperledger/besu/controller/BesuController.java