code: public static <E> DocumentFragment<Mutation> convertToSubDocumentResult(ResponseStatus status, Mutation mutation, E element) {
          return new DocumentFragment<Mutation>(null, 0, null,
                  Collections.singletonList(SubdocOperationResult.createResult(null, mutation, status, element)));
      }
docs: Useful for mapping exceptions of Multimutation or to be silent by mapping success to a valid subdocument result
  
  @return document fragment result