on method
Implementation
@override
void on(String eventName, EventHandler<T> handler) {
var handlers = _events[eventName];
if (handlers == null) {
handlers = [];
_events[eventName] = handlers;
}
if (handlers.isEmpty) {
_messageClient.sendInstanceEventAdd(
_instanceId,
_namespace ?? '',
eventName,
);
}
handlers.add(handler);
}