code: public FlinkKafkaConsumerBase<T> setStartFromGroupOffsets() {
  		this.startupMode = StartupMode.GROUP_OFFSETS;
  		this.startupOffsetsTimestamp = null;
  		this.specificStartupOffsets = null;
  		return this;
  	}
docs: Specifies the consumer to start reading from any committed group offsets found
  in Zookeeper / Kafka brokers. The "group.id" property must be set in the configuration
  properties. If no offset can be found for a partition, the behaviour in "auto.offset.reset"
  set in the configuration properties will be used for the partition.
  
  <p>This method does not affect where partitions are read from when the consumer is restored
  from a checkpoint or savepoint. When the consumer is restored from a checkpoint or
  savepoint, only the offsets in the restored state will be used.
  
  @return The consumer object, to allow function chaining.