code: func hostNetworkSystemFromHostSystem(hs *object.HostSystem) (*object.HostNetworkSystem, error) {
  	ctx, cancel := context.WithTimeout(context.Background(), defaultAPITimeout)
  	defer cancel()
  	return hs.ConfigManager().NetworkSystem(ctx)
  }
docs: // hostNetworkSystemFromHostSystem locates a HostNetworkSystem from a specified
  // HostSystem.