gzip-stream

To create a valid gzip from many individual streams first use createDeflatePart() which returns a through stream to convert your parts to the deflated part. when this through stream emits the 'end' event you should call its metadata() function which will give you back an object in the form of { len, zLen, digest }

To create the final stream pass an array of objects in the form of { stream: your_readable_stream, len, zLen, digest } to createGzipStream() and you'll get back a readable stream that also has a zLen property containing the total bytes of the compressed stream.