agent/ecscni/plugin.go
func (client *cniClient) del(runtimeConfig libcni.RuntimeConf,
	cfg *Config,
	pluginConfigFunc func(*Config) (string, *libcni.NetworkConfig, error)) error {

	deviceName, networkConfig, err := pluginConfigFunc(cfg)
	if err != nil {
		return err
	}
	runtimeConfig.IfName = deviceName

	return client.libcni.DelNetwork(networkConfig, &runtimeConfig)
}
func (client *cniClient) del(runtimeConfig libcni.RuntimeConf,
	cfg *Config,
	pluginConfigFunc func(*Config) (string, *libcni.NetworkConfig, error)) error {

	deviceName, networkConfig, err := pluginConfigFunc(cfg)
	if err != nil {
		return err
	}
	runtimeConfig.IfName = deviceName

	return client.libcni.DelNetwork(networkConfig, &runtimeConfig)
}
// del invokes the DEL command of the given plugin