查询当前资金费率

curl https://cloud-api.wooxpro.com/contract/public/funding-rate?symbol=BTCUSDT

{
  "code": 1000,
  "message": "Ok",
  "data": {
    "timestamp": 1662518172178,
    "symbol": "BTCUSDT",
    "rate_value": "0.000164",
    "expected_rate": "0.000164",
    "funding_time": 1709971200000,
    "funding_upper_limit": "0.0375",
    "funding_lower_limit": "-0.0375"
  },
  "trace": "13f7fda9-9543-4e11-a0ba-cbe117989988"
}