From 8f71f010f696f6d094b124dcb325a410a7d4e5f4 Mon Sep 17 00:00:00 2001
From: Alessio Dalla Piazza <alessio.dallapiazza@gmail.com>
Date: Tue, 19 Nov 2024 15:54:31 +0100
Subject: [PATCH] avoid canonicalization

---
 proxy.go | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/proxy.go b/proxy.go
index 3deecfb0..b50cae86 100644
--- a/proxy.go
+++ b/proxy.go
@@ -44,9 +44,8 @@ func copyHeaders(dst, src http.Header, keepDestHeaders bool) {
 		}
 	}
 	for k, vs := range src {
-		for _, v := range vs {
-			dst.Add(k, v)
-		}
+		// direct assignment to avoid canonicalization
+		dst[k] = append([]string(nil), vs...)
 	}
 }