duplicate(overrideStartupNodes = [], overrideOptions = {}) {
        const startupNodes = overrideStartupNodes.length > 0
            ? overrideStartupNodes
            : this.startupNodes.slice(0);
        const options = Object.assign({}, this.options, overrideOptions);
        return new Cluster(startupNodes, options);
    }
Create a new instance with the same startup nodes and options as the current one.

@example
```js
var cluster = new Redis.Cluster([{ host: "127.0.0.1", port: "30001" }]);
var anotherCluster = cluster.duplicate();
```

@public
@param {((string | number | object)[])} [overrideStartupNodes=[]]
@param {IClusterOptions} [overrideOptions={}]
@memberof Cluster