From 84f6845bf2238bd05eda9afd556f4a6fed42b60d Mon Sep 17 00:00:00 2001
From: Nylonicious <50183564+nylonicious@users.noreply.github.com>
Date: Tue, 24 Aug 2021 13:21:02 +0200
Subject: [PATCH] stream: impl FromIterator for StreamMap (#4052)

---
 tokio-stream/src/stream_map.rs | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/tokio-stream/src/stream_map.rs b/tokio-stream/src/stream_map.rs
index 9dc529ac0..80a521ee1 100644
--- a/tokio-stream/src/stream_map.rs
+++ b/tokio-stream/src/stream_map.rs
@@ -568,6 +568,23 @@ where
     }
 }
 
+impl<K, V> std::iter::FromIterator<(K, V)> for StreamMap<K, V>
+where
+    K: Hash + Eq,
+{
+    fn from_iter<T: IntoIterator<Item = (K, V)>>(iter: T) -> Self {
+        let iterator = iter.into_iter();
+        let (lower_bound, _) = iterator.size_hint();
+        let mut stream_map = Self::with_capacity(lower_bound);
+
+        for (key, value) in iterator {
+            stream_map.insert(key, value);
+        }
+
+        stream_map
+    }
+}
+
 mod rand {
     use std::cell::Cell;