配置在stream段：
log_format proxy '$remote_addr [$time_local]' '$protocol $status $bytes_sent $bytes_received' '$session_time "$upstream_addr" ' '"$upstream_bytes_sent" "$upstream_bytes_received" "$upstream_connect_time"';access_log /var/log/nginx/tcp-access.log proxy ;error_log /var/log/nginx/tcp-error.log warn ;
