chore: import upstream snapshot with attribution

doc/source/serve/doc_code/fastapi_example.py

@@ -0,0 +1,23 @@
+import requests
+from fastapi import FastAPI
+from ray import serve
+
+# 1: Define a FastAPI app and wrap it in a deployment with a route handler.
+app = FastAPI()
+
+
+@serve.deployment
+@serve.ingress(app)
+class FastAPIDeployment:
+    # FastAPI will automatically parse the HTTP request for us.
+    @app.get("/hello")
+    def say_hello(self, name: str) -> str:
+        return f"Hello {name}!"
+
+
+# 2: Deploy the deployment.
+serve.run(FastAPIDeployment.bind(), route_prefix="/")
+
+# 3: Query the deployment and print the result.
+print(requests.get("http://localhost:8000/hello", params={"name": "Theodore"}).json())
+# "Hello Theodore!"