Verify the consumer received all the messages. You should see:
...
Consumed record with key alice and value {"Count":0}, and updated total count to 0
Consumed record with key alice and value {"Count":1}, and updated total count to 1
Consumed record with key alice and value {"Count":2}, and updated total count to 3
Consumed record with key alice and value {"Count":3}, and updated total count to 6
Consumed record with key alice and value {"Count":4}, and updated total count to 10
Consumed record with key alice and value {"Count":5}, and updated total count to 15
Consumed record with key alice and value {"Count":6}, and updated total count to 21
Consumed record with key alice and value {"Count":7}, and updated total count to 28
Consumed record with key alice and value {"Count":8}, and updated total count to 36
Consumed record with key alice and value {"Count":9}, and updated total count to 45
...