onVisibilityChange property Null safety

Stream<Event> onVisibilityChange
@SupportedBrowser(SupportedBrowser.CHROME), @SupportedBrowser(SupportedBrowser.FIREFOX), @SupportedBrowser(SupportedBrowser.IE, '10')

Implementation

@SupportedBrowser(SupportedBrowser.CHROME)
@SupportedBrowser(SupportedBrowser.FIREFOX)
@SupportedBrowser(SupportedBrowser.IE, '10')
Stream<Event> get onVisibilityChange => visibilityChangeEvent.forTarget(this);