Function crypto_crawler::crawl_candlestick

pub fn crawl_candlestick(
    exchange: &str, 
    market_type: MarketType, 
    symbol_interval_list: Option<&[(String, usize)]>, 
    tx: Sender<Message>, 
    duration: Option<u64>
)

Crawl candlestick(i.e., OHLCV) data.

If symbol_interval_list is None or empty, this API will crawl candlesticks from 10 seconds to 3 minutes(if available) for all symbols.