Whether descendants of this widget are allowed to add semantic information to the SemanticsNode annotated by this widget.
When set to false descendants are allowed to annotate SemanticsNodes of their parent with the semantic information they want to contribute to the semantic tree. When set to true the only way for descendants to contribute semantic information to the semantic tree is to introduce new explicit SemanticsNodes to the tree.
This setting is often used in combination with SemanticsConfiguration.isSemanticBoundary to create semantic boundaries that are either writable or not for children.
final bool explicitChildNodes