addListener method
Adds a synchronous listener to the event. Synchronous listeners are called immediately and should complete quickly. They are executed before any asynchronous listeners. Parameters:
listener- The function to call when the event is emitted Returns this Event instance for method chaining. Example:
event.addListener((data) => print('Event: $data'))
.addListener((data) => updateCounter());
Implementation
Event addListener(EventFunction listener) {
_listeners.add(listener);
return this;
}