chentaiyue

fix the rare case of infinite loop

1

[The function `randomLevel`](https://github.com/flower-corp/rosedb/blob/main/ds/zset/zset.go#L449) has a very low probability to fall into an infinite loop. Besides, we can use `rand.Float64()` to generate a pseudo-random number between 0.0 and 1.0, instead of...

Hello, I have a problem about how to generate prior anchor. Could you give me source code about it. Thanks in advance.