code: public DataBulkRequest insertBefore(CRUDRequest request, CRUDRequest before) {
          this.requests.add(requests.indexOf(before), request);
          return this;
      }
docs: Inserts a request before another specified request. This guarantees that
  the first request parameter will be executed, sequentially, before the
  second request parameter. It does not guarantee consecutive execution.
  
  @param request
  @param before
  @return