title: Duplicate offsets in a Kafka topic with more than one partition
body: <p>I am using <code>kafka_2.10-0.10.0.1</code> with <code>zookeeper-3.4.10</code>. I know that there are many types of offsets. I have two questions:
  - I want to know the type of the offset returned by <code>ConsumerRecord.offset().</code>
  - If I use a topic created with 10 partitions, can I obtain a set of records with the same offset value? In my program, I need to obtain a list of records with different offset values. I want to know do I have to use a topic with a single partition to achieve this goal?</p>