How to use payload - 1 common examples

export async function fetchPayload(context: IPlayContext, boxId: string): Promise
{
    const payloadUrl = `${context.payloadBaseUrl}/${boxId}_payload.json`;

    const payloadContent = await fetch.json(payloadUrl, "GET") as IPlayPayload;
    const payloadFileName = context.files["payload.json"] = context.boxDir + "/payload.json";
    const payloadFilePath = path.resolve(context.job.jobDir, payloadFileName);

    // fetch and write thumbnail image
    const thumbImage = await fetch.buffer(payloadContent.message.pubThumb, "GET");
    const thumbFileName = context.files["image-thumb.jpg"] = "image-thumb.jpg";
    const thumbFilePath = path.resolve(context.job.jobDir, thumbFileName);

    // fetch and write preview image
    const previewImage = await fetch.buffer(payloadContent.message.pubPreview, "GET");
    const previewFileName = context.files["image-preview.jpg"] = "image-preview.jpg";
    const previewFilePath = path.resolve(context.job.jobDir, previewFileName);

    return Promise.all([
        fs.writeFile(payloadFilePath, JSON.stringify(payloadContent, null, 2)),
        fs.writeFile(thumbFilePath, Buffer.from(thumbImage)),
        fs.writeFile(previewFilePath, Buffer.from(previewImage))