message: expand premetheus.ipynb server startup time.
  This is still failing, even in Colab with restart-and-run-all.
diff: "\n",
  "# Give the server a few seconds to startup.\n",
  "import time\n",
  - "time.sleep(10)"
  + "time.sleep(20)"
  ],
  "execution_count": 0,
  "outputs": []
  