Option to send/receive binary data

[ancarda]

This package currently uses JSON, but I would really like to be able to send and receive raw binary data through this, specifically I'd like to be able to send Google\Cloud\PubSub\Message and have that along with attributes be received by other, possibly non-PHP, clients that are listening to PubSub.

I've been using a modified version of this package that (now) includes a decode_json flag in the config to disable calling json_encode and json_decode. Is there interest in me submitting these changes so they can live upstream? I'm more than happy to put in the work so these changes can be merged.

If the answer is no, please let me know so I can publish the code separately.