func GetMulti(c context.Context, key []string) (map[string]*Item, error) {
	if len(key) == 0 {
		return nil, nil
	}
	keyAsBytes := make([][]byte, len(key))
	for i, k := range key {
		keyAsBytes[i] = []byte(k)
	}
	req := &pb.MemcacheGetRequest{
		Key:    keyAsBytes,
		ForCas: proto.Bool(true),
	}
	res := &pb.MemcacheGetResponse{}
	if err := internal.Call(c, "memcache", "Get", req, res); err != nil {
		return nil, err
	}
	m := make(map[string]*Item, len(res.Item))
	for _, p := range res.Item {
		t := protoToItem(p)
		m[t.Key] = t
	}
	return m, nil
}
func GetMulti(c context.Context, key []string) (map[string]*Item, error) {
	if len(key) == 0 {
		return nil, nil
	}
	keyAsBytes := make([][]byte, len(key))
	for i, k := range key {
		keyAsBytes[i] = []byte(k)
	}
	req := &pb.MemcacheGetRequest{
		Key:    keyAsBytes,
		ForCas: proto.Bool(true),
	}
	res := &pb.MemcacheGetResponse{}
	if err := internal.Call(c, "memcache", "Get", req, res); err != nil {
		return nil, err
	}
	m := make(map[string]*Item, len(res.Item))
	for _, p := range res.Item {
		t := protoToItem(p)
		m[t.Key] = t
	}
	return m, nil
}
// GetMulti is a batch version of Get. The returned map from keys to items may
// have fewer elements than the input slice, due to memcache cache misses.
// Each key must be at most 250 bytes in length.