{
  "jsonrpc": "2.0",
  "method": "public/subscribe",
  "id": 42,
  "params": {
    "channels": [
      "perpetual.BTC-PERPETUAL.100ms"
    ]
  }
}

{
  "data": {
    "interest": 0.004999511380756577,
    "timestamp": 1571386349530,
    "index_price": 7872.88
  }
}