Redis cluster 查询优化 #3586

Is your feature request related to a problem?
RedisClusterChannel::CallMethodImpl 看着是把redis命令折分出来一个个执行的. 每次一个完整 RTT 地串行发，没有任何 pipeline、也没有并发。

Describe the solution you'd like
是否可以对key先按 slot分组 + 每次发一个真正的批量请求 + 并发发送

Describe alternatives you've considered

N/A
Additional context/screenshots

N/A