code: func (client *cniClient) createIPAMNetworkConfig(cfg *Config) (string, *libcni.NetworkConfig, error) {
  	ipamConfig, err := client.createIPAMConfig(cfg)
  	if err != nil {
  		return defaultVethName, nil, errors.Wrap(err, "createIPAMNetworkConfig: create ipam network configuration failed")
  	}
  
  	ipamNetworkConfig := IPAMNetworkConfig{
  		Name:       ECSIPAMPluginName,
  		CNIVersion: client.cniVersion,
  		IPAM:       ipamConfig,
  	}
  
  	networkConfig, err := client.constructNetworkConfig(ipamNetworkConfig, ECSIPAMPluginName)
  	if err != nil {
  		return "", nil, errors.Wrap(err, "createIPAMNetworkConfig: construct ipam network configuration failed")
  	}
  	return defaultVethName, networkConfig, nil
  }
docs: // createIPAMNetworkConfig constructs the ipam configuration accepted by libcni