docs: update streaming example (#1321)

* docs: update streaming example

examples/streaming-content.ipynb

@@ -14,9 +14,24 @@
     "Below is a simple toy example."
    ]
   },
+  {
+   "cell_type": "markdown",
+   "id": "95301021-1db9-426f-807c-ec5b37bd5a9d",
+   "metadata": {},
+   "source": [
+    "<div class=\"admonition warning\">\n",
+    "    <p class=\"admonition-title\">ASYNC IN PYTHON<=3.10</p>\n",
+    "    <p>\n",
+    "Any Langchain RunnableLambda, a RunnableGenerator, or Tool that invokes other runnables and is running async in python<=3.10, will have to propagate callbacks to child objects manually. This is because LangChain cannot automatically propagate callbacks to child objects in this case.\n",
+    "    \n",
+    "This is a common reason why you may fail to see events being emitted from custom runnables or tools.\n",
+    "    </p>\n",
+    "</div>"
+   ]
+  },
   {
    "cell_type": "code",
-   "execution_count": 4,
+   "execution_count": 1,
    "id": "486a01a0",
    "metadata": {},
    "outputs": [],
@@ -51,7 +66,10 @@
     "    messages = []\n",
     "    # Tagging a node makes it easy to filter out which events to include in your stream\n",
     "    # It's completely optional, but useful if you have many functions with similar names\n",
-    "    gen = RunnableGenerator(my_generator).with_config(tags=[\"should_stream\"])\n",
+    "    gen = RunnableGenerator(my_generator).with_config(\n",
+    "        tags=[\"should_stream\"],\n",
+    "        callbacks=config.get(\"callbacks\", [])  # <-- Propagate callbacks (Python <= 3.10)\n",
+    "    )\n",
     "    async for message in gen.astream(state):\n",
     "        messages.append(message)\n",
     "    return {\"messages\": [AIMessage(content=\" \".join(messages))]}\n",
@@ -65,7 +83,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 5,
+   "execution_count": 2,
    "id": "ce773a40",
    "metadata": {},
    "outputs": [
@@ -80,7 +98,7 @@
      "name": "stderr",
      "output_type": "stream",
      "text": [
-      "/Users/harrisonchase/.pyenv/versions/3.11.1/envs/permchain/lib/python3.11/site-packages/langchain_core/_api/beta_decorator.py:87: LangChainBetaWarning: This API is in beta and may change in the future.\n",
+      "/Users/vadymbarda/.virtualenvs/langgraph/lib/python3.11/site-packages/langchain_core/_api/beta_decorator.py:87: LangChainBetaWarning: This API is in beta and may change in the future.\n",
       "  warn_beta(\n"
      ]
     }
@@ -89,7 +107,7 @@
     "from langchain_core.messages import HumanMessage\n",
     "\n",
     "inputs = [HumanMessage(content=\"What are you thinking about?\")]\n",
-    "async for event in app.astream_events({\"messages\": inputs}, version=\"v1\"):\n",
+    "async for event in app.astream_events({\"messages\": inputs}, version=\"v2\"):\n",
     "    kind = event[\"event\"]\n",
     "    tags = event.get(\"tags\", [])\n",
     "    if kind == \"on_chain_stream\" and \"should_stream\" in tags:\n",
@@ -104,7 +122,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "id": "2c7b7902-2d80-4bf9-91c1-737b749e58a3",
+   "id": "615cb9d2-bfa2-4f83-90b0-c6c2d1e6df95",
    "metadata": {},
    "outputs": [],
    "source": []
@@ -112,9 +130,9 @@
  ],
  "metadata": {
   "kernelspec": {
-   "display_name": "Python 3 (ipykernel)",
+   "display_name": "langgraph",
    "language": "python",
-   "name": "python3"
+   "name": "langgraph"
   },
   "language_info": {
    "codemirror_mode": {
@@ -126,7 +144,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.11.1"
+   "version": "3.11.9"
   }
  },
  "nbformat": 4,