Optimize how MQClientAPIExt is obtained in the MQClientAPIFactory

[socutes]

To discuss whether this problem needs to be optimized:
The getClient method in the current MQClientAPIFactory. The MQClientAPIExt is obtained by random seeds.In extreme cases, load imbalance on MQClientAPIExt may occur.
You are advised to change the obtaining mode from random to polling.

#6312

[echooymxq]

用轮询应该需要一个并发计数器了，性能并不一定好.

[socutes]

Its advantage is that when there are many clients, the traffic can be guaranteed to be balanced. @xdkxlk What do you think?

[xdkxlk]

Its advantage is that when there are many clients, the traffic can be guaranteed to be balanced. @xdkxlk What do you think?

I think using random should be enough. The getClient method will be called frequently, so the distribution overall should be relatively even.