function EventMultiplexer() {
            var _this = this;
            this.hasListeners = false;
            this.events = [];
            this.emitter = new Emitter({
                onFirstListenerAdd: function () { return _this.onFirstListenerAdd(); },
                onLastListenerRemove: function () { return _this.onLastListenerRemove(); }
            });
        }
To be kept private to fire an event to
subscribers