Allow to pass the file through the stream

[ksmithut]

Using the stream functionality, It would be awesome if I could pass the stream through the other side.

Example:

1. Accept a read stream
2. pass the read stream through clamav.js
3. pass the now verified read stream to a gzip stream
4. pass the gzipped stream through an encryption stream
5. pass the stream to the write stream (external storage service like s3 or just the file system)

The line of code I'm looking at is here: https://github.com/yongtang/clamav.js/blob/master/index.js#L120

It seems to be swallowing the callback I would need to reuse the stream. Or perhaps this is already supported?

[ksmithut]

Nevermind, we found a different way of doing it. We're just going to split the stream and have one stream pipe into clam, and the other save the file and mark it as unopenable until clam does it's thing.