code: @InterfaceAudience.Public
      public Document getDocument() {
          if (getDocumentId() == null) {
              return null;
          }
          assert (database != null);
          Document document = database.getDocument(getDocumentId());
          document.loadCurrentRevisionFrom(this);
          return document;
      }
docs: The document this row was mapped from.  This will be nil if a grouping was enabled in
  the query, because then the result rows don't correspond to individual documents.