public EventHubsInputDescriptor<StreamMessageType> withConsumerGroup(String consumerGroup) {
    this.consumerGroup = Optional.ofNullable(StringUtils.stripToNull(consumerGroup));
    return this;
  }
Set the consumer group from the upstream Event Hubs entity that the consumer is part of. Defaults to the
<code>$Default</code> group that is initially present in all Event Hubs entities (unless removed)

@param consumerGroup the name of the consumer group upstream
@return this input descriptor
samza-azure/src/main/java/org/apache/samza/system/eventhub/descriptors/EventHubsInputDescriptor.java