fix: Close connection when set keepalive failed

[ArisAachen]

When the server incorrectly returns a Content-Length value smaller than the actual data length, reading the data based on the declared length will inevitably leave unread data in the buffer. This results in a failure to set up keepalive for connection reuse. According to the source code of request_uri, such keepalive failures are not explicitly returned to the caller. In this scenario, the best approach is to ​proactively close the connection to prevent resource leaks.