How to use the @terascope/teraslice-messaging.ClusterMaster.Server function in @terascope/teraslice-messaging

module.exports = function _clusterMaster(context) {
    const logger = makeLogger(context, 'cluster_master');
    const clusterConfig = context.sysconfig.teraslice;
    const assetsPort = process.env.assets_port;
    const assetsUrl = `http://127.0.0.1:${assetsPort}`;
    let running = false;

    // Initialize the HTTP service for handling incoming requests.
    const app = express();

    const clusterMasterServer = new ClusterMaster.Server({
        port: clusterConfig.port,
        nodeDisconnectTimeout: clusterConfig.node_disconnect_timeout,
        // setting request timeout to 5 minutes
        serverTimeout: 300000,
        // we do this to override express final response handler
        requestListener(req, res) {
            app(req, res, (err) => {
                if (err) logger.warn(err, 'unexpected server error');
                res.setHeader('Content-Type', 'application/json');
                res.statusCode = 500;
                res.end(JSON.stringify({ error: 'api is not available' }));
            });
        },
        networkLatencyBuffer: clusterConfig.network_latency_buffer,
        actionTimeout: clusterConfig.action_timeout,
        logger,