请求报文格式

订阅

{
    "method": "subscribe",
    "params": [
        "ticker@btc_usdt",
        "depth@btc_usdt"
    ],
    "id": 1              //回调ID
}

取消订阅

{
    "method": "unsubscribe",
    "params": [
        "ticker@btc_usdt"
    ],
    "id": 2              //回调ID
}