Apache httpd在400个响应上关闭连接

Question

我已经观察到，无论keepalive设置如何，只要响应代码为400，我们的apache httpd服务器都会返回Connection: close。可以修改此行为，还是在任何地方进行记录？我能找到的最接近的文档是here：

IF
    we have not marked this connection as errored;
and
    the client isn't expecting 100-continue
and
    the response status does not require a close;
and
    the response body has a defined length due to the status code being 304 or 204, the request method being HEAD, already having defined Content-Length or Transfer-Encoding: chunked, or the request version being HTTP/1.1 and thus capable of being set as chunked
THEN
    we support keepalive.

关键行是and the response status does not require a close;。