Implement Stream::size_hint() for Either (#2325)

rust-lang · Jan 19, 2021 · aa784fc · aa784fc
1 parent 0ae6d1e
commit aa784fc
Showing 1 changed file with 7 additions and 0 deletions.
diff --git a/futures-util/src/future/either.rs b/futures-util/src/future/either.rs
@@ -101,6 +101,13 @@ where
             Either::Right(x) => x.poll_next(cx),
         }
     }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        match self {
+            Either::Left(x) => x.size_hint(),
+            Either::Right(x) => x.size_hint(),
+        }
+    }
 }
 
 impl<A, B> FusedStream for Either<A, B>