This example demonstrates an eventing mechanism for Swift, showing how to create type-safe events with multiple handlers and automatic cleanup. It defines an `Event<T>` class that manages a collection of handler wrappers, allowing observers to subscribe and unsubscribe dynamically. The implementation uses the `Disposable` protocol for tear-down logic and the `Invocable` private protocol to abstract handler invocation, with `EventHandlerWrapper` holding a weak reference to the target to prevent retain cycles. The code highlights Swift’s protocol-oriented and generics features, as well as curried instance methods, to build a reusable notification system without relying on external libraries.