Should input parameter in controller be Mono in Webflux?

Should the controller method expect a Mono?

@GetMapping("/resource/{id}")
fun getPayouts(request: Mono<Request>): Flux<Result> {

    return request.flatMapMany {
        service.processRequest(it)
    }
}

While the Request object looks like

@ApiModel
class Request {
    @NotNull
    var id: Long? = null

    @NotNull
    @DateTimeFormat(iso = DateTimeFormat.ISO.DATE)
    var start: LocalDate? = null

    @NotNull
    @DateTimeFormat(iso = DateTimeFormat.ISO.DATE)
    var end: LocalDate? = null
}

I wasn't successful in finding docs on that. Maybe you can point me in the right direction