EventDefinition
Ties one EventSchema subtype to everything mosaic-client needs to execute it — the unit passed in MosaicDependencyInjectionConfig.eventDefinitions to register a custom event, and the shape every built-in event's own XEventDefinition object follows. MosaicModules uses eventSchemaClass to build the framework's MosaicSerializer registration, eventRunner to build the EventRunnerManager lookup table, and eventHolderBuilder to build the EventHolderBuilderManager lookup table — one Definition feeds all three, so registering a custom event is exactly this one object, nothing more.