To retrieve the subscribers for a topic, use the getSubscribers method.
This method returns a Map of subscribers for a topic or object of all subscribers for all topics.

const subscribers = eventBus.getSubscribers('myTopic')

The Map contains the callback and an object with the subscriber options.

The subscriber options contain the callCount of how many times the subscriber has been notified.

subscribers.forEach((callback, options) => {
  // how many times this subscriber has been called