viewerPerformanceWatchdogMixin

将PerformanceWatchdog小部件添加到Viewer小部件的混合。此函数通常作为参数传递给Viewer#extend，而不是直接调用，如下例所示。
Parameters:
viewer (Viewer) 查看器实例。
options (Object) 具有属性的对象。
Name Description
options.lowFrameRateMessage
String
default 'This application appears to be performing poorly on your system. Please try using a different web browser or updating your video drivers.' 		检测到低帧速率时要显示的消息。消息以HTML形式插入，因此请确保它来自受信任的源，这样您的应用程序就不会受到跨站点脚本攻击的攻击。
Example
var viewer = new bmgl.Viewer('container');
viewer.extend(bmgl.viewerPerformanceWatchdogMixin, {
    lowFrameRateMessage : 'Why is this going so <em>slowly</em>?'
});
Throws