/* GET /market/detail/merged?symbol=ethusdt */
{
"status":"ok",
"ch":"market.ethusdt.detail.merged",
"ts":1499225276950,
"tick":{
  "id":1499225271,
  "ts":1499225271000,
  "close":"1885.0000",
  "open":"1960.0000",
  "high":"1985.0000",
  "low":"1856.0000",
  "amount":81486.2926,
  "count":42122,
  "vol":157052744.85708200,
  "ask":[1885.0000, 21.8804],
  "bid":[1884.0000, 1.6702]
  }
}

/* GET /market/detail/merged?symbol=not-exist */
{
  "ts": 1490758171271,
  "status": "error",
  "err-code": "invalid-parameter",
  "err-msg": "invalid symbol”
}