code: func NewHandlerFromVolumeDriver(d volume.Driver) *volumeplugin.Handler {
  	return volumeplugin.NewHandler(&shimDriver{d})
  }
docs: // NewHandlerFromVolumeDriver creates a plugin handler from an existing volume
  // driver. This could be used, for instance, by the `local` volume driver built-in
  // to Docker Engine and it would create a plugin from it that maps plugin API calls
  // directly to any volume driver that satifies the volume.Driver interface from
  // Docker Engine.