===== AsyncTopic =====

[[AsyncTopic]] is the base interface used to define asynchronous Message Broker topics. It is used by the [[IMessageBroker]] to constrain a broadcast to the asynchronous messaging flow and to bind the Topic to the type of [[BaseMessage]] it carries.

Topics implement ''AsyncTopic<T>'', where T specifies the message payload accepted by that Topic and must derive from [[BaseMessage]]. This association ensures that subscriptions and broadcasts for a Topic use the corresponding message type.

An AsyncTopic is intended to represent a specific event or notification whose subscribers may perform asynchronous work. Subscribers register an [[AsyncEventCallback]] for an AsyncTopic and a specific broadcaster. When that broadcaster asynchronously broadcasts the Topic, the [[IMessageBroker]] executes all associated callbacks and waits for their Tasks to complete.

=== Type Parameters ===
^Type Parameter | T |
^Description | The [[BaseMessage]] type associated with the AsyncTopic. This determines the payload type that can be supplied when subscribing to or asynchronously broadcasting the Topic. |