onStart method
Called at the exact moment the widget is allocated in memory. It uses an internal "callable" type, to avoid any @overrides in subclasses. This method should be internal and is required to define the lifetime cycle of the subclass.
Implementation
// @protected
@mustCallSuper
@nonVirtual
void onStart() {
if (_initialized) {
return;
}
onInit();
_initialized = true;
}