From 57db73454768d30f82805c1972df5c97fac65a36 Mon Sep 17 00:00:00 2001
From: Jamie Hewland <jhewland@gmail.com>
Date: Thu, 23 Apr 2020 22:16:36 +0200
Subject: [PATCH] Workaround potential infinite loop in StreamingResponse

---
 starlette/responses.py | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/starlette/responses.py b/starlette/responses.py
index 143e9e014..d993b1389 100644
--- a/starlette/responses.py
+++ b/starlette/responses.py
@@ -1,3 +1,4 @@
+import asyncio
 import hashlib
 import http.cookies
 import inspect
@@ -202,6 +203,11 @@ async def listen_for_disconnect(self, receive: Receive) -> None:
             message = await receive()
             if message["type"] == "http.disconnect":
                 break
+            # Relinquish control to the event loop to allow it to check if
+            # stream_response has completed. The receive() call above may not have
+            # handed control over to the loop, especially if there isn't actually a
+            # network between us and the client (e.g. when testing).
+            await asyncio.sleep(0)
 
     async def stream_response(self, send: Send) -> None:
         await send(