chore: import upstream snapshot with attribution

tests/llama_index/sample_code/simple_workflow.py

@@ -0,0 +1,37 @@
+from llama_index.core.workflow import (
+    Event,
+    StartEvent,
+    StopEvent,
+    Workflow,
+    step,
+)
+from llama_index.llms.openai import OpenAI
+
+import mlflow
+
+
+class JokeEvent(Event):
+    joke: str
+
+
+class JokeFlow(Workflow):
+    llm = OpenAI()
+
+    @step
+    async def generate_joke(self, ev: StartEvent) -> JokeEvent:
+        topic = ev.topic
+        prompt = f"Write your best joke about {topic}."
+        response = await self.llm.acomplete(prompt)
+        return JokeEvent(joke=str(response))
+
+    @step
+    async def critique_joke(self, ev: JokeEvent) -> StopEvent:
+        joke = ev.joke
+
+        prompt = f"Give a thorough analysis and critique of the following joke: {joke}"
+        response = await self.llm.acomplete(prompt)
+        return StopEvent(result=str(response))
+
+
+w = JokeFlow(timeout=10, verbose=False)
+mlflow.models.set_model(w)