From dfa6623a244da9c07a359541d7789c8fc8293f78 Mon Sep 17 00:00:00 2001
From: David Tolnay <dtolnay@gmail.com>
Date: Wed, 19 Apr 2017 14:56:52 -0700
Subject: [PATCH] Encourage serialize_entry

---
 serde/src/ser/mod.rs | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/serde/src/ser/mod.rs b/serde/src/ser/mod.rs
index 6472909b..bf92563f 100644
--- a/serde/src/ser/mod.rs
+++ b/serde/src/ser/mod.rs
@@ -1634,6 +1634,11 @@ pub trait SerializeMap {
     type Error: Error;
 
     /// Serialize a map key.
+    ///
+    /// If possible, `Serialize` implementations are encouraged to use
+    /// `serialize_entry` instead as it may be implemented more efficiently in
+    /// some formats compared to a pair of calls to `serialize_key` and
+    /// `serialize_value`.
     fn serialize_key<T: ?Sized>(&mut self, key: &T) -> Result<(), Self::Error>
     where
         T: Serialize;