extendStates method
Calls the extend function for each state that has been defined, allowing the states to be
extended with additional metadata and filters.
The extend function is provided with a state key identifying the state to extemd, and a
StateExtensionBuilder that can be used to define the extensions.
Implementation
DeclarativeStateTreeBuilder extendStates(
void Function(StateKey, StateExtensionBuilder) extend) {
for (var entry in _stateBuilders.entries) {
extend(entry.key, StateExtensionBuilder._(entry.value));
}
return this;
}