[Bug] 使用lmdeploy serve proxy 分发服务管理下游服务，导致stream模式丢失

[Gierry]

Checklist

• 1. I have searched related issues but cannot get the expected help.
• 2. The bug has not been fixed in the latest version.
• 3. Please note that if the bug-related issue you submitted lacks corresponding environment info and a minimal reproducible demo, it will be challenging for us to reproduce and resolve the issue, reducing the likelihood of receiving feedback.

Describe the bug

使用lmdeploy serve proxy --server-port 8000 --strategy "min_expected_latency"
启动分发服务，导致原本的stream模式丢失，变成了结果是最后一次性输出(几十条信息一次性输出)，而不是拟人效果
通过直接调用下游分支端口，实际正常，所以怀疑问题出现在代理服务这里。

启动参数
lmdeploy serve proxy --server-port 8000 --strategy "min_expected_latency"

Reproduction

none

Environment

lmdeploy==0.7.1

Error traceback

[AllentDan]

多高的并发？

[Gierry]

多高的并发？

@AllentDan 本地测试，就我自己一个人测试都这样

[AllentDan]

复现不了