refactor log_subrequest
diff --git a/src/http/ngx_http_request.h b/src/http/ngx_http_request.h
index 6368398..2486ca5 100644
--- a/src/http/ngx_http_request.h
+++ b/src/http/ngx_http_request.h
@@ -464,6 +464,7 @@
     unsigned                          expect_tested:1;
     unsigned                          root_tested:1;
     unsigned                          done:1;
+    unsigned                          logged:1;
     unsigned                          utf8:1;
 
     unsigned                          buffered:4;