groupId property Null safety
final
An optional group ID that groups TapRegions together so that they operate as one region. If any member of a group is hit by a particular tap, then the onTapOutside will not be called for any members of the group. If any member of the group is hit, then all members will have their onTapInside called.
If the group id is null, then only this region is hit tested.
Implementation
final Object? groupId;