code: function(errorMessage) {
                      var errorResponse = {};
  
                      if (errorMessage) {
                          errorResponse.error = errorMessage;
                      }
  
                      log(qq.format("Failed to generate blob for ID {}.  Error message: {}.", id, errorMessage), "error");
  
                      options.onComplete(id, options.getName(id), qq.extend(errorResponse, preventRetryResponse), null);
                      upload.maybeSendDeferredFiles(id);
                      connectionManager.free(id);
                  }
docs: Blob could not be generated.  Fail the upload & attempt to prevent retries.  Also bubble error message.