chore: import upstream snapshot with attribution

doc/source/serve/doc_code/model_composition/streaming_example.py

@@ -0,0 +1,42 @@
+# flake8: noqa
+# __streaming_example_start__
+# File name: stream.py
+from typing import AsyncGenerator, Generator
+
+from ray import serve
+from ray.serve.handle import DeploymentHandle, DeploymentResponseGenerator
+
+
+@serve.deployment
+class Streamer:
+    def __call__(self, limit: int) -> Generator[int, None, None]:
+        for i in range(limit):
+            yield i
+
+
+@serve.deployment
+class Caller:
+    def __init__(self, streamer: DeploymentHandle):
+        self._streamer = streamer.options(
+            # Must set `stream=True` on the handle, then the output will be a
+            # response generator.
+            stream=True,
+        )
+
+    async def __call__(self, limit: int) -> AsyncGenerator[int, None]:
+        # Response generator can be used in an `async for` block.
+        r: DeploymentResponseGenerator = self._streamer.remote(limit)
+        async for i in r:
+            yield i
+
+
+app = Caller.bind(Streamer.bind())
+
+handle: DeploymentHandle = serve.run(app).options(
+    stream=True,
+)
+
+# Response generator can also be used as a regular generator in a sync context.
+r: DeploymentResponseGenerator = handle.remote(10)
+assert list(r) == list(range(10))
+# __streaming_example_end__