[core rpc][Feature Request] Remove unused client_pool and check if the connection succeeded

[ykwd]

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• I searched the issues and found no similar issues.

We’re very glad to have the chance to use the latest client pools feature in coro_rpc. While using it, we’ve encountered a couple of issues:

1. When using coro_io::client_pools, if a new server address appears, the pools will automatically create a new client pool. However, there’s currently no interface to remove an existing client pool. If the addresses keep changing and are always different from the previous ones, this can potentially lead to a resource leak.

2. When creating a new client pool using the at interface of pools, there is no return value indicating whether the connection was successful. Currently, our workaround is to create a dedicated API on the remote server to test connectivity. Having a native way to check whether the connection succeeds would be more user-friendly.

What happened + What you expected to happen

Reproduction way

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Are you willing to submit a PR?

• Yes I am willing to submit a PR!

[poor-circle]

the cient_pools::at() is always successful, because we wont create a new connection immiediately.

[ykwd]

the cient_pools::at() is always successful, because we wont create a new connection immiediately.

Thanks for the quick reply. Sorry, I didn’t notice the notification earlier. Is there a way to check whether the connection was successful?

[qicosmos]

client pool is lazy, it's empty at the beginning, it will create clients when used(call pool.send_request).

https://github.com/kvcache-ai/Mooncake/blob/main/mooncake-store/src/master_client.cpp#L140
check the return value, if failed means the client from the pool connecting failed or expired.