{
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  "method": "lastprice_request",
  "params": [
    "ETH_BTC"
  ]
}

{
  "id": 6,
  "method": "lastprice_subscribe",
  "params": [
    "ETH_BTC",
    "BTC_USDT"
  ]
}

{
  "id": 7,
  "method": "lastprice_unsubscribe",
  "params": []
}

{
  "id": 5,
  "result": "0.020553",
  "error": null
}

{
  "id": 6,
  "result": {
    "status": "success"
  },
  "error": null
}

{
  "id": null,
  "method": "lastprice_update",
  "params": [
    "ETH_BTC",
    "0.020683"
  ]
}