[master] 40bd73b8f fetch: Apply the debug::flush_head flag to bereq

[Dridi Boukelmoune]

commit 40bd73b8fc08ae5d0880b1693da27e46f083e248
Author: Dridi Boukelmoune <dridi.boukelmoune at gmail.com>
Date:   Fri Apr 8 19:15:50 2022 +0200

    fetch: Apply the debug::flush_head flag to bereq

diff --git a/bin/varnishd/http1/cache_http1_fetch.c b/bin/varnishd/http1/cache_http1_fetch.c
index 1a2ced1e8..5ea77b936 100644
--- a/bin/varnishd/http1/cache_http1_fetch.c
+++ b/bin/varnishd/http1/cache_http1_fetch.c
@@ -111,6 +111,8 @@ V1F_SendReq(struct worker *wrk, struct busyobj *bo, uint64_t *ctr_hdrbytes,
 		    bo, vbf_iter_req_body, 0);
 	} else if (bo->req != NULL &&
 	    bo->req->req_body_status != BS_NONE) {
+		if (DO_DEBUG(DBG_FLUSH_HEAD))
+			(void)V1L_Flush(wrk);
 		if (do_chunked)
 			V1L_Chunked(wrk);
 		i = VRB_Iterate(wrk, bo->vsl, bo->req, vbf_iter_req_body, bo);