Add stream mode example

main.py

@@ -0,0 +1,13 @@
+import os
+from langchain.chat_models import ChatOpenAI
+from langchain.schema import HumanMessage
+
+# Example of streaming with LangChain
+if __name__ == "__main__":
+    # Use OpenAI API key from env
+    os.environ.setdefault("OPENAI_API_KEY", "sk-...")
+    model = ChatOpenAI(temperature=0.7)
+    # Stream response
+    for chunk in model.stream([HumanMessage(content="Hello, world!" )]):
+        print(chunk.content, end="", flush=True)
+    print("\n[Done]")