  /**
   *  Returns a non-terminating observable sequence, which can be used to denote an infinite duration (e.g. when using reactive joins).
   * @returns {Observable} An observable sequence whose observers will never get called.
   */
  var observableNever = Observable.never = function () {
    return new AnonymousObservable(function () {
      return disposableEmpty;
    });
  };
