mosquitto_pub -h 172.20.10.12 -t co2/esp32 -m "{
  "metadata": {
    "timestamp": "2025-04-12T14:22:35Z",
    "mac": "AA:BB:CC:DD:EE:FF",
    "room": "A123"
  },
  "co2": 615.3,
  "temperature": 21.8,
  "humidity": 45.2
}"