Function crypto_crawler::crawl_trade

pub fn crawl_trade<'a>(
    exchange: &str, 
    market_type: MarketType, 
    symbols: &[String], 
    on_msg: Arc<Mutex<dyn FnMut(Message) + Send + 'a>>, 
    duration: Option<u64>
)

Crawl trades.

If symbols is None, this function will crawl all trading symbols of in the market_type, and fetch the latest symbols every hour.