From 73f100fa66900305820fb30c5beaac274dcd54e9 Mon Sep 17 00:00:00 2001
From: DioCrafts <pozo.dionisio@gmail.com>
Date: Tue, 3 Mar 2026 19:48:53 +0100
Subject: [PATCH] perf(h1): pre-allocate read buffer to avoid early
 reallocations

Change read_buf initialization from BytesMut::with_capacity(0) to
BytesMut::with_capacity(INIT_BUFFER_SIZE) (8192 bytes).

The read buffer almost always grows to INIT_BUFFER_SIZE on the first read.
Pre-allocating avoids the initial zero-capacity allocation and the
subsequent reallocation + copy when the first data arrives.
---
 src/proto/h1/io.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/proto/h1/io.rs b/src/proto/h1/io.rs
index 6a30d73c84..9f78e993f8 100644
--- a/src/proto/h1/io.rs
+++ b/src/proto/h1/io.rs
@@ -68,7 +68,7 @@ where
             io,
             partial_len: None,
             read_blocked: false,
-            read_buf: BytesMut::with_capacity(0),
+            read_buf: BytesMut::with_capacity(INIT_BUFFER_SIZE),
             read_buf_strategy: ReadStrategy::default(),
             write_buf,
         }