From a36eee80f09e7bf35ad66d5ba7ca10104ef0ee63 Mon Sep 17 00:00:00 2001
From: Wez Furlong <wez@wezfurlong.org>
Date: Thu, 24 Aug 2023 12:21:02 -0700
Subject: [PATCH] message: make retain_headers more efficient

Avoid an intermediate string allocation; we can write directly
to the new buffer.
---
 crates/message/src/message.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crates/message/src/message.rs b/crates/message/src/message.rs
index 78ab0443..d2e200a7 100644
--- a/crates/message/src/message.rs
+++ b/crates/message/src/message.rs
@@ -651,7 +651,7 @@ impl Message {
             if !retain {
                 continue;
             }
-            new_data.extend_from_slice(hdr.to_header_string().as_bytes());
+            hdr.write_header(&mut new_data)?;
         }
         new_data.extend_from_slice(b"\r\n");
         new_data.extend_from_slice(&data[body_offset..]);