jsonResponse 
  inline fun <T : Any> jsonResponse(body: T, init: ResponseInit = ResponseInit(
        status = 200,
        statusText = "OK",
        headers = Headers().apply {
            jsonContentType()
        }
    )): Response(source)
Creates a Response with json content-type header and body as body. The response status (200 by default) and headers can be changed by supplying init.