addListener method
Implementation
void addListener(String name, EventCallback callback) {
List<EventCallback>? list = _callbacks[name];
if (list == null) {
list = [];
_callbacks[name] = list;
}
list.add(callback);
}
void addListener(String name, EventCallback callback) {
List<EventCallback>? list = _callbacks[name];
if (list == null) {
list = [];
_callbacks[name] = list;
}
list.add(callback);
}