From 8138afbfadd0b7f2640a28d9c0af0f59a59e3967 Mon Sep 17 00:00:00 2001
From: k-nasa <htilcs1115@gmail.com>
Date: Fri, 18 Oct 2019 12:20:02 +0900
Subject: [PATCH] feat: Add Stream trait for Flatten

---
 src/stream/stream/flatten.rs | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/src/stream/stream/flatten.rs b/src/stream/stream/flatten.rs
index 06e9ec2..5c76167 100644
--- a/src/stream/stream/flatten.rs
+++ b/src/stream/stream/flatten.rs
@@ -54,6 +54,19 @@ impl<S: Stream<Item: IntoStream>> Flatten<S> {
     }
 }
 
+impl<S, U> Stream for Flatten<S>
+where
+    S: Stream<Item: IntoStream<IntoStream = U, Item = U::Item>> + std::marker::Unpin,
+    U: Stream + std::marker::Unpin,
+{
+    type Item = U::Item;
+
+    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
+        self.as_mut().inner().poll_next(cx)
+    }
+}
+
+
 /// Real logic of both `Flatten` and `FlatMap` which simply delegate to
 /// this type.
 #[derive(Clone, Debug)]