add NoMessages setting which disables Messages(), and PartitionStartNotification callback
add NoMessages setting which disables Messages(), and PartitionStartNotification callback

These two together (along with InOrderDone) let you implement your own message fetching and processing
while letting this package implement the group consumer parts. When PartitionStartNotification is called,
start consuming the partition at the given offset, and call Done periodically.
When AssignmentNotification indicates the partition is no longer
assigned, stop consuming it (and typically usually, commit the final offset)

mistsys/sarama-consumer