block4.js

var data_stream = new ReadableStream();//new stream.Readable();
  var gzip = zlib.createGzip();

  // create parameters hash for table scan
  var params = {TableName: tablename, ReturnConsumedCapacity: 'NONE', Limit: '1'};

  // body will contain the compressed content to ship to s3
  var body = data_stream.pipe(gzip);

  var s3obj = new aws.S3({params: {Bucket: 'ccu-dynamo-backups', Key: tablename + '/' + tablename + '-' + ts + '.gz'}});
  s3obj.upload({Body: body}).
    on('httpUploadProgress', function(evt) {
      console.log(evt);
    }).
    send(function(err, data) { console.log(err, data); callback(); });