From 8509936e8f48c64c063b7ba858b881377007f416 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jakub=20D=C4=85bek?= <jakub.dabek@gmail.com>
Date: Sun, 14 Aug 2022 11:01:04 +0200
Subject: [PATCH] Add mention of `BufReader` in `Read::bytes` docs

---
 library/std/src/io/mod.rs | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/library/std/src/io/mod.rs b/library/std/src/io/mod.rs
index 96addbd1a0558..a16e2431ea9fc 100644
--- a/library/std/src/io/mod.rs
+++ b/library/std/src/io/mod.rs
@@ -883,6 +883,10 @@ pub trait Read {
     /// The yielded item is [`Ok`] if a byte was successfully read and [`Err`]
     /// otherwise. EOF is mapped to returning [`None`] from this iterator.
     ///
+    /// The default implementation calls `read` for each byte,
+    /// which can be very inefficient for data that's not in memory,
+    /// such as [`File`]. Consider using a [`BufReader`] in such cases.
+    ///
     /// # Examples
     ///
     /// [`File`]s implement `Read`:
@@ -895,10 +899,11 @@ pub trait Read {
     /// ```no_run
     /// use std::io;
     /// use std::io::prelude::*;
+    /// use std::io::BufReader;
     /// use std::fs::File;
     ///
     /// fn main() -> io::Result<()> {
-    ///     let f = File::open("foo.txt")?;
+    ///     let f = BufReader::new(File::open("foo.txt")?);
     ///
     ///     for byte in f.bytes() {
     ///         println!("{}", byte.unwrap());