Fix uncaught exception occurring when reading in a message containing non-unicode bytes

[abaruni]

also, some doc updates and test updates

[abaruni]

could not find a way to effectively create a scala test for this. i can test manually and verify the change works. i've attempted to create a python action to write non-unicode message to kafka. problem is that the non-unicode bytes get escaped when reading in the file while creating the action. manually invoking the action works. but i don't see away around the encoding and escaping/replacing that java/scala do. perhaps there is a way. i'm just struggling to find it at the moment

[abaruni]

@dubeejw would you mind having a look