preallocating slices (#904)

* preallocated some slices when size is known

* gofmt

* gofmt

store/cloudflare/cloudflare.go

@@ -123,7 +123,7 @@ func (w *workersKV) List() ([]*store.Record, error) {
 		return nil, errors.New(messages)
 	}
 
-	var keys []string
+	keys := make([]string, 0, len(a.Result))
 
 	for _, r := range a.Result {
 		keys = append(keys, r.Name)

store/etcd/etcd.go

@@ -32,7 +32,7 @@ func (e *ekv) Read(keys ...string) ([]*store.Record, error) {
 		values = append(values, keyval.Kvs...)
 	}
 
-	var records []*store.Record
+	records := make([]*store.Record, 0, len(values))
 
 	for _, kv := range values {
 		records = append(records, &store.Record{