  
  func breakWithError(error: ErrorType);
  
  var error:ErrorType? {get}
  var force:Bool {get set}
  var status:OperationStatus {get set}
  var stage:OperationStage {get set}
  var data:NSData? {get set}
  var results:[AnyObject]? {get set}
  var convertedObject:AnyObject? {get set}