{
  "functions": [
    {
      "function": 3,
      "name": "read_holding_registers",
      "request": [
        {"name":"starting_address","type":"u16"},
        {"name":"quantity","type":"u16"}
      ],
      "response": [
        {"name":"byte_count","type":"u8"},
        {"name":"registers","type":"bytes","length_from":"byte_count"}
      ]
    }
  ]
}