onTapOutside property Null safety
final
A callback to be invoked when a tap is detected outside of this TapRegion and any other region with the same groupId, if any.
The PointerDownEvent passed to the function is the event that caused the notification. If this region is part of a group (i.e. groupId is set), then it's possible that the event may be outside of this immediate region, although it will be within the region of one of the group members.
Implementation
final TapRegionCallback? onTapOutside;