Eventable is the interface reactors and other modules must export to become eventable.

EventData is a generic event data can be typed and registered with tendermint/go-amino via concrete implementation of this interface.

EventSwitch is the interface for synchronous pubsub, where listeners subscribe to certain events and, when an event is fired (see Fireable), notified via a callback function.

Fireable is the interface that wraps the FireEvent method.