public Boolean getSendKeyInEventProperties(String systemName) {
    String isSendKeyIncluded = get(String.format(CONFIG_SEND_KEY_IN_EVENT_PROPERTIES, systemName));
    if (isSendKeyIncluded == null) {
      return DEFAULT_CONFIG_SEND_KEY_IN_EVENT_PROPERTIES;
    }
    return Boolean.valueOf(isSendKeyIncluded);
  }
Returns true if the OutgoingMessageEnvelope key should be sent in the outgoing envelope, false otherwise

@param systemName name of the system
@return Boolean, is send key included
samza-azure/src/main/java/org/apache/samza/system/eventhub/EventHubConfig.java