function main() {
    var accounts = [];
    while (true) {
        for (var i = 0; i < exchanges.length; i++) {
            if (accounts[i] == null) {
                // 创建异步操作
                accounts[i] = exchanges[i].Go("GetAccount");
            }
        }
        var failed = 0;
        for (var i = 0; i < exchanges.length; i++) {
            if (typeof(accounts[i].wait) != "undefined") {