Whether the semantics node is a live region.
A live region indicates that updates to semantics node are important. Platforms may use this information to make polite announcements to the user to inform them of updates to this node.
An example of a live region is a SnackBar widget. On Android and iOS, live region causes a polite announcement to be generated automatically, even if the widget does not have accessibility focus. This announcement may not be spoken if the OS accessibility services are already announcing something else, such as reading the label of a focused widget or providing a system announcement.
static const SemanticsFlag isLiveRegion = SemanticsFlag._(_kIsLiveRegionIndex, 'isLiveRegion');