func (cd Codec) SetMulti(c context.Context, items []*Item) error {
	return cd.set(c, items, pb.MemcacheSetRequest_SET)
}
func (cd Codec) SetMulti(c context.Context, items []*Item) error {
	return cd.set(c, items, pb.MemcacheSetRequest_SET)
}
// SetMulti is a batch version of Set.
// appengine.MultiError may be returned.