Available on js
@:optionaloptionalsignal:Null<AbortSignal>
@:optionaloptionalreferrerPolicy:Null<ReferrerPolicy>
@:optionaloptionalreferrer:Null<String>
@:optionaloptionalredirect:Null<RequestRedirect>
@:optionaloptionalobserve:Null<EitherType<FetchObserver ‑> Void, ObserverCallback>>
@:optionaloptionalmode:Null<RequestMode>
@:optionaloptionalmethod:Null<String>
@:optionaloptionalintegrity:Null<String>
@:optionaloptionalheaders:Null<EitherType<Headers, EitherType<Array<Array<String>>, DynamicAccess<String>>>>
@:optionaloptionalcredentials:Null<RequestCredentials>
@:optionaloptionalcache:Null<RequestCache>
@:optionaloptionalbody:Null<EitherType<Blob, EitherType<EitherType<ArrayBufferView, ArrayBuffer>, EitherType<FormData, EitherType<URLSearchParams, String>>>>>