Method fetchTicker

java/lib/src/main/java/io/github/ccxt/exchanges/OkxCore.java:2325–2368

@method @name okx#fetchTicker @description fetches a price ticker, a statistical calculation with the information calculated over the past 24 hours for a specific market @see https://www.okx.com/docs-v5/en/#order-book-trading-market-data-get-ticker @param {string} symbol unified symbol of the market

(Object symbol, Object... optionalArgs)

     * @returns {object} a [ticker structure]{@link https://docs.ccxt.com/?id=ticker-structure}
     */
    public java.util.concurrent.CompletableFuture<Object> fetchTicker(Object symbol, Object... optionalArgs)
    {

        return java.util.concurrent.CompletableFuture.supplyAsync(() -> {

            Object parameters = Helpers.getArg(optionalArgs, 0, new java.util.HashMap<String, Object>() {{}});
            (this.loadMarkets()).join();
            Object market = this.market(symbol);
            Object request = new java.util.HashMap<String, Object>() {{
                put( "instId", Helpers.GetValue(market, "id") );
            }};
            Object response = (this.publicGetMarketTicker(this.extend(request, parameters))).join();
            //
            //     {
            //         "code": "0",
            //         "msg": "",
            //         "data": [
            //             {
            //                 "instType": "SPOT",
            //                 "instId": "ETH-BTC",
            //                 "last": "0.07319",
            //                 "lastSz": "0.044378",
            //                 "askPx": "0.07322",
            //                 "askSz": "4.2",
            //                 "bidPx": "0.0732",
            //                 "bidSz": "6.050058",
            //                 "open24h": "0.07801",
            //                 "high24h": "0.07975",
            //                 "low24h": "0.06019",
            //                 "volCcy24h": "11788.887619",
            //                 "vol24h": "167493.829229",
            //                 "ts": "1621440583784",
            //                 "sodUtc0": "0.07872",
            //                 "sodUtc8": "0.07345"
            //             }
            //         ]
            //     }
            //
            Object data = this.safeList(response, "data", new java.util.ArrayList<Object>(java.util.Arrays.asList()));
            Object first = this.safeDict(data, 0, new java.util.HashMap<String, Object>() {{}});
            return this.parseTicker(first, market);
        });

    }

    /**
     * @method