iter, err := db.BuildIterator(CursorQuery{
        start:  NewDBKey(uint32(time.Now().Add(-time.Hour).Unix()), types.BytesToTopic(topic), types.Hash{}).Bytes(),
        end:    NewDBKey(uint32(time.Now().Add(time.Second).Unix()), types.BytesToTopic(topic), types.Hash{}).Bytes(),
        topics: [][]byte{topic},
        limit:  10,