code: function assetStream(sourceFolder, maxAge) {
  
    if (maxAge === null || !isFinite(maxAge)) {
      maxAge = 3600;
    }
  
    console.log("Using max-age " + maxAge);
  
    if (!sourceFolder) {
      sourceFolder = 'dist';
    }
  
    var headers = {
      'Cache-Control': sprintf('max-age=%d, public', maxAge)
    };
  
    // Select everything BUT the entrypoints
    var src = entryPoints.map(f => "!" + f)
    src.unshift('**/*.*')
  
    return vfs.src(src, {
        cwd: sourceFolder
      })
      .pipe(through2((file, enc, cb) => {
        s3Init(file)
        Object.assign(file.s3.headers, headers)
        cb(null, file)
      }))
  }
docs: /*
  Get file streams for all hashed assets
  (assets with rev urls)
  
  targetFolder -- folder to publish into
  maxAge -- expiry age for header