code: public Map<String, Object> buildAdminProperties() {
  		Map<String, Object> properties = buildCommonProperties();
  		properties.putAll(this.admin.buildProperties());
  		return properties;
  	}
docs: Create an initial map of admin properties from the state of this instance.
  <p>
  This allows you to add additional properties, if necessary, and override the
  default kafkaAdmin bean.
  @return the admin properties initialized with the customizations defined on this
  instance