ssize_t rdbSaveAuxField(rio *rdb, void *key, size_t keylen, void *val, size_t vallen) {
    ssize_t ret, len = 0;
    if ((ret = rdbSaveType(rdb,RDB_OPCODE_AUX)) == -1) return -1;
    len += ret;
    if ((ret = rdbSaveRawString(rdb,key,keylen)) == -1) return -1;
    len += ret;
    if ((ret = rdbSaveRawString(rdb,val,vallen)) == -1) return -1;
    len += ret;
    return len;
}
ssize_t rdbSaveAuxField(rio *rdb, void *key, size_t keylen, void *val, size_t vallen) {
    ssize_t ret, len = 0;
    if ((ret = rdbSaveType(rdb,RDB_OPCODE_AUX)) == -1) return -1;
    len += ret;
    if ((ret = rdbSaveRawString(rdb,key,keylen)) == -1) return -1;
    len += ret;
    if ((ret = rdbSaveRawString(rdb,val,vallen)) == -1) return -1;
    len += ret;
    return len;
}