Change log:
- Process decorator now has two new parameters: accepts and returns
- accepts parameter is used to indicate how kaf should parse the message values before passing to the user function.
- If accepts='bytes' then the raw message is passed
- If accepts='json' then kaf will attempt to parse the output of json.loads
- returns parameter is used to indicate how kaf should handle the values returned from the user function
- If returns='bytes' then kaf will pass the value directly to Kafka
- If returns='json' then kaf will serialize the value using json.dumps(value).encode('utf-8')