MarketDataRequest - Real-Time

Examples of Real-Time requests:

- Order Book Snapshot + Updates : 263=1, 264=0, 265=0, 267/269=0,267/269=1, 146/207=huobi, 146/55=btc_usd
- Order Book Snapshots          : 263=0, 264=0, 265=0, 267/269=0,267/269=1, 146/207=huobi, 146/55=btc_usd
- Order Book Updates            : 263=1, 264=0, 265=1, 267/269=0,267/269=1, 146/207=huobi, 146/55=btc_usd
- Trades                        : 263=1, 264=0, 265=1, 267/269=2,           146/207=huobi, 146/55=btc_usd
- OHLCV                         : 263=0, 264=0, 265=0, 267/269=3,           146/207=huobi, 146/55=btc_usd