Modify the _send_done_recv_signal method to properly handle socket cleanup by using a socket_valid flag.

[xleoken]

What this PR does / why we need it?

Modify the _send_done_recv_signal method to properly handle socket cleanup by using a socket_valid flag.

Does this PR introduce any user-facing change?

How was this patch tested?

• vLLM version: main
• vLLM main: vllm-project/vllm@29799dd

[gemini-code-assist]

Code Review

This pull request introduces a socket_valid flag to improve socket cleanup in the _send_done_recv_signal method. This is a good step towards preventing faulty sockets from being reused. However, the current implementation only considers the case of an invalid ACK response. My review highlights that other exceptions during socket communication are not handled, which could still lead to a broken socket being returned to the connection pool. I've suggested a more comprehensive exception handling strategy to make the socket cleanup logic more robust.

[github-actions]

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