call method
Implementation
@override
Object? call(Interpreter interpreter, List<Object?> arguments,
Map<Symbol, Object?> namedArguments) {
var preferredSize = namedArguments[const Symbol('preferredSize')];
if (preferredSize == null) {
throw "preferredSize required in PreferredSizeWidget";
}
var child = namedArguments[const Symbol('child')];
if (child == null) {
throw "child required in PreferredSizeWidget";
}
return PreferredSize(
child: child as Widget, preferredSize: preferredSize as Size);
}