Request
constructor(url: String = "", method: String = "", headers: Map<String, String> = emptyMap(), body: dynamic = undefined, referrer: String? = undefined, referrerPolicy: dynamic = undefined, mode: RequestMode? = undefined, credentials: RequestCredentials? = undefined, cache: RequestCache? = undefined, redirect: RequestRedirect? = undefined, integrity: String? = undefined, keepalive: Boolean? = undefined, reqWindow: Any? = undefined, middlewares: List<Middleware> = emptyList())