Kaffe v0.5.0 Kaffe.Worker
A worker is assigned a single partition across topics for the client. This is so we effectively serialize the processing of any single key across topics.
Processing the message set is delegated to the configured message handler. It
is responsible for any error handling. The message handler must define a
handle_messages
function (note the pluralization!) to accept a list of
messages.
The result of handle message is sent back to the subscriber.