Verify the consumer received all the messages. You should see:
Subscribing to test1, waiting for assignment and messages...
Press Ctrl-C to exit.
Received message on test1 [0] at offset 0: { "count": 1 }
User alice sum 1
Received message on test1 [0] at offset 1: { "count": 2 }
User alice sum 3
Received message on test1 [0] at offset 2: { "count": 3 }
User alice sum 6
Received message on test1 [0] at offset 3: { "count": 4 }
User alice sum 10
Received message on test1 [0] at offset 4: { "count": 5 }
User alice sum 15
Received message on test1 [0] at offset 5: { "count": 6 }
User alice sum 21
Received message on test1 [0] at offset 6: { "count": 7 }
User alice sum 28
Received message on test1 [0] at offset 7: { "count": 8 }
User alice sum 36
Received message on test1 [0] at offset 8: { "count": 9 }
User alice sum 45
Received message on test1 [0] at offset 9: { "count": 10 }
User alice sum 55