createElement method Null safety
Inflates this configuration to a concrete instance.
A given widget can be included in the tree zero or more times. In particular a given widget can be placed in the tree multiple times. Each time a widget is placed in the tree, it is inflated into an Element, which means a widget that is incorporated into the tree multiple times will be inflated multiple times.
@override ParentDataElement<T> createElement() => ParentDataElement<T>(this);