[DISCUSS] SEP-8: Add in-memory system consumer & producer

[Bharath Kumara Subramanian]

Hi all,

I have created SEP-8 for in-memory system support.
Please find the design doc here
<https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=71013043>

Let me know your thoughts and feedback.

Thanks,
Bharath