code: public R call() throws BackendException {
          while (hasNext) {
              pagesProcessed++;
              next();
          }
          delegate.updatePagesHistogram(apiName, tableName, pagesProcessed);
          return getMergedPages();
      }
docs: Paginates through pages of an entity.
  @return an encapsulation of the pages of an entity
  @throws BackendException if there was any trouble paginating