From c1b260d90f7016426511cb2f7db747bb00cf67eb Mon Sep 17 00:00:00 2001
From: Bertrand Bousquet <b.kamek@gmail.com>
Date: Tue, 3 Jul 2018 12:31:06 -0400
Subject: [PATCH] Document panic on header index (#223)

---
 src/header/map.rs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/header/map.rs b/src/header/map.rs
index 93a2c62..09f1614 100644
--- a/src/header/map.rs
+++ b/src/header/map.rs
@@ -1864,6 +1864,8 @@ impl<'a, K, T> ops::Index<K> for HeaderMap<T>
 {
     type Output = T;
 
+    /// # Panics
+    /// Using the index operator will cause a panic if the header you're querying isn't set.
     #[inline]
     fn index(&self, index: K) -> &T {
         self.get(index).expect("no entry found for key")