Created attachment 34133 [details]
Add log message when apr_socket_send fails

Function apr_socket_send may fail. The majority of calls have checked the return value and printed log message like the following code snippet, while the others have not. Those unchecked ones probably need logs too (see attachment).

/* httpd-2.4.10/modules/proxy/mod_proxy_scgi.c:234:19 */
        if ((rv = apr_socket_send(conn->sock, buf, &written)) != APR_SUCCESS) {
            ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r, APLOGNO(00858)
                          "sending data to %s:%u failed",
                          conn->hostname, conn->port);
        }