如何在Golang Kafka 10中获取GroupID？

I am using Kafka 10.0 and https://github.com/Shopify/sarama. I am trying to get the offset of the latest message that a consumer processed.

To do so I've found the method NewOffsetManagerFromClient(group string, client Client) which require the group name.

How do I get consumer group name?

offsets := make(map[int32]int64)

config := sarama.NewConfig()
config.Consumer.Offsets.CommitInterval = 200 * time.Millisecond
config.Version = sarama.V0_10_0_0

// config.Consumer.Offsets.Initial = sarama.OffsetNewest
cli, _ := sarama.NewClient(kafkaHost, config)
defer cli.Close()

offsetManager, _ := sarama.NewOffsetManagerFromClient(group, cli)
for _, partition := range partitions {
    partitionOffsetManager, _ := offsetManager.ManagePartition(topic, partition)
    offset, _ := partitionOffsetManager.NextOffset()

    offsets[partition] = offset
}
return offsets

I created a consumer with

consumer := sarama.NewConsumer(connections, config)

but I do not know how to create a consumer group and get its group name.