body:Null<EitherType<ArrayBuffer, EitherType<ArrayBufferView, EitherType<Blob, EitherType<FormData, EitherType<String, URLSearchParams>>>>>>
cache:Null<RequestCache>
credentials:Null<RequestCredentials>
headers:Null<EitherType<Headers, EitherType<Array<Array<String>>, Dynamic>>>
method:Null<String>
mode:Null<RequestMode>
redirect:Null<RequestRedirect>
referrer:Null<String>
referrerPolicy:Null<ReferrerPolicy>