code: public void marshall(User user, ProtocolMarshaller protocolMarshaller) {
  
          if (user == null) {
              throw new SdkClientException("Invalid argument passed to marshall(...)");
          }
  
          try {
              protocolMarshaller.marshall(user.getId(), ID_BINDING);
              protocolMarshaller.marshall(user.getUsername(), USERNAME_BINDING);
              protocolMarshaller.marshall(user.getEmailAddress(), EMAILADDRESS_BINDING);
              protocolMarshaller.marshall(user.getGivenName(), GIVENNAME_BINDING);
              protocolMarshaller.marshall(user.getSurname(), SURNAME_BINDING);
              protocolMarshaller.marshall(user.getOrganizationId(), ORGANIZATIONID_BINDING);
              protocolMarshaller.marshall(user.getRootFolderId(), ROOTFOLDERID_BINDING);
              protocolMarshaller.marshall(user.getRecycleBinFolderId(), RECYCLEBINFOLDERID_BINDING);
              protocolMarshaller.marshall(user.getStatus(), STATUS_BINDING);
              protocolMarshaller.marshall(user.getType(), TYPE_BINDING);
              protocolMarshaller.marshall(user.getCreatedTimestamp(), CREATEDTIMESTAMP_BINDING);
              protocolMarshaller.marshall(user.getModifiedTimestamp(), MODIFIEDTIMESTAMP_BINDING);
              protocolMarshaller.marshall(user.getTimeZoneId(), TIMEZONEID_BINDING);
              protocolMarshaller.marshall(user.getLocale(), LOCALE_BINDING);
              protocolMarshaller.marshall(user.getStorage(), STORAGE_BINDING);
          } catch (Exception e) {
              throw new SdkClientException("Unable to marshall request to JSON: " + e.getMessage(), e);
          }
      }
docs: Marshall the given parameter object.