How to use the faastjs.Statistics function in faastjs

export async function mapBucket(Bucket: string, keyFilter: (key: string) => boolean) {
    const faastModule = await faast("aws", m, {
        memorySize: 2048,
        timeout: 300,
        mode: "queue",
        concurrency: 2000,
        childProcess: true,
        gc: "off"
        // awsLambdaOptions: { TracingConfig: { Mode: "Active" } }
    });
    console.log(`Logs: ${faastModule.logUrl()} `);
    faastModule.on("stats", s => {
        console.log(`${s}`);
    });

    const bandwidth = new Statistics();

    try {
        let allObjects = await listAllObjects(Bucket);
        allObjects = allObjects.filter(obj => keyFilter(obj.Key!));
        const promises = [];
        console.log(`Bucket ${Bucket} contains ${allObjects.length} matching objects`);
        const start = Date.now();
        for (const Obj of allObjects) {
            promises.push(
                faastModule.functions
                    .processBucketObject(Bucket, Obj.Key!)
                    .catch((err: FaastError) => {
                        console.log(`Error processing ${Obj.Key!}`);
                        console.log(`Logs: ${err.logUrl}`);
                    })
            );

const workload = (Bucket: string, filter: FilterFn) => async (
    faastModule: FaastModule
) => {
    const remote = faastModule.functions;
    let allObjects = await listAllObjects(Bucket);
    allObjects = allObjects.filter(obj => filter(obj.Key!));
    const promises = [];
    const start = Date.now();
    for (const Obj of allObjects) {
        promises.push(remote.processBucketObject(Bucket, Obj.Key!));
        break;
    }
    const results = await Promise.all(promises);
    const elapsed = Date.now() - start;
    let bytes = 0;
    const bandwidth = new Statistics();
    for (const result of results) {
        if (!result) {
            continue;
        }
        bytes += result.bytes;
        bandwidth.update(result.bandwidthMbps);
    }
    const metrics: BandwidthMetrics = {
        bytesGB: bytes / GB,
        bandwidthMbps: bandwidth.mean
    };
    return metrics;
};