chore: import upstream snapshot with attribution

tests/fastapi/streaming_app.py

@@ -0,0 +1,30 @@
+from collections.abc import AsyncIterator
+
+from fastapi import FastAPI
+from starlette.responses import StreamingResponse
+
+from agents import Agent, Runner, RunResultStreaming
+
+agent = Agent(
+    name="Assistant",
+    instructions="You are a helpful assistant.",
+)
+
+
+app = FastAPI()
+
+
+@app.post("/stream")
+async def stream():
+    result = Runner.run_streamed(agent, input="Tell me a joke")
+    stream_handler = StreamHandler(result)
+    return StreamingResponse(stream_handler.stream_events(), media_type="application/x-ndjson")
+
+
+class StreamHandler:
+    def __init__(self, result: RunResultStreaming):
+        self.result = result
+
+    async def stream_events(self) -> AsyncIterator[str]:
+        async for event in self.result.stream_events():
+            yield f"{event.type}\n\n"