  var InnerSubscription = function (s, o) {
    this._s = s;
    this._o = o;
  };

  InnerSubscription.prototype.dispose = function () {
    if (!this._s.isDisposed && this._o !== null) {
      var idx = this._s.observers.indexOf(this._o);
      this._s.observers.splice(idx, 1);
      this._o = null;
    }
  };
