tapRegionObjectId property
Optional group ID that lets this button's built-in TapRegion act as one region together with other TapRegion/SInkButton widgets sharing the same id. Passed straight through to TapRegion.groupId.
A tap on the button itself is always considered "inside" its own
region, so groupId is only needed when several separate regions
(e.g. this button plus a related overlay) should count as one area for
onTapOutside/onTapInside purposes.
Implementation
final Object? tapRegionObjectId;