react
fun <S> react(processor: String, function: String, stateType: Class<S & Any>?, blocking: Boolean = false, startFrom: StartFrom? = null, aggregates: List<String> = emptyList(), nullableState: Boolean = stateType == null, retry: HandlerRetry? = null, eventType: Class<*>? = null, handle: suspend (StateEvent<S>, SubscriptionContext) -> Unit): ProcessorBinding<S>
A @Reactor's handler function of processor; of each event of the eventType when it gives one.