Asynchronous publish-subscribe communication library.
Features:
1. Listeners are stored using WeakReferences to prevent memory leaks when they are not unsubscribed.
2. Uses fork-join framework for concurrent event delivery.
3. Publish methods returns collection of Futures that represent event notifications.
4. Supports ordered publishing: guaranteed to notify of the events in order they were published.
5. Provides EventSource and EventService interfaces for better integration with IOC containers and alternative implementations.