# viewerPerformanceWatchdogMixin

Widgets/Viewer/viewerPerformanceWatchdogMixin.js 26
A mixin which adds the `PerformanceWatchdog` widget to the `Viewer` widget. Rather than being called directly, this function is normally passed as a parameter to `Viewer#extend`, as shown in the example below.

##### Example:

    var viewer = new Cesium.Viewer('cesiumContainer');
    viewer.extend(Cesium.viewerPerformanceWatchdogMixin, {
        lowFrameRateMessage : 'Why is this going so <em>slowly</em>?'
    });