EventContentToEventSerializerMappings
constructor(baseMapping: Set<EventContentSerializerMapping<C>>, eventDeserializer: (EventContentSerializerMapping<C>) -> KSerializer<E>, eventSerializer: (EventContentSerializerMapping<C>) -> KSerializer<E> = eventDeserializer, unknownEventSerializer: (String) -> KSerializer<U>, typeField: String? = "type")