Allows you to subscribe to public topics. 
subscribe(
  topic: string | { [key:string]:any },
  callback: WSMessageHandler | Omit<WSMessageHandler, "onUnsubscribe">,
  once?: boolean,
  id?: string
): unsubscribe | undefined
Subscribing to the trade topic: 
const ws = useWS();

useEffect(() => {
  const unsubscribe = ws.subscribe(
    {
      id: `${symbol}@trade`,
      event: "subscribe",
      topic: `${symbol}@trade`,
      ts: Date.now()
    },
    {
      onMessage: (data: any) => {
        //
      }
    }
  );
  () => {
    // Unsubscribes when the component unloads
    unsubscribe();
  };
}, []);

​
Subscribing to private topics

Subscribing to the executionreport topic: 
const ws = useWS();

useEffect(() => {
  const unsubscript = ws.privateSubscribe(
    {
      id: "executionreport",
      event: "subscribe",
      topic: "executionreport",
      ts: Date.now()
    },
    {
      onMessage: (data) => {
        // do something
      }
    }
  );
  () => {
    // Unsubscribes when the component unloads
    unsubscribe();
  };
}, []);