Verify the producer sent all the messages. You should see:
Preparing to produce record: alice 0
Preparing to produce record: alice 1
Preparing to produce record: alice 2
Preparing to produce record: alice 3
Preparing to produce record: alice 4
Preparing to produce record: alice 5
Preparing to produce record: alice 6
Preparing to produce record: alice 7
Preparing to produce record: alice 8
Successfully produced record to topic test1 partition [5] @ offset 117
Successfully produced record to topic test1 partition [5] @ offset 118
Successfully produced record to topic test1 partition [5] @ offset 119
Successfully produced record to topic test1 partition [5] @ offset 120
Successfully produced record to topic test1 partition [5] @ offset 121
Successfully produced record to topic test1 partition [5] @ offset 122
Successfully produced record to topic test1 partition [5] @ offset 123
Successfully produced record to topic test1 partition [5] @ offset 124
Successfully produced record to topic test1 partition [5] @ offset 125