A mock requests that was received and is ready to be answered.
class TestRequest { readonly cancelled: boolean; override request: HttpRequest<any>; flush(body: string | number | boolean | Object | ArrayBuffer | Blob | (string | number | boolean | Object)[], opts?: { headers?: any; status?: number; statusText?: string; }): void; error(error: ErrorEvent, opts?: TestRequestErrorOptions): void; error(error: ProgressEvent<EventTarget>, opts?: TestRequestErrorOptions): void; event(event: HttpEvent<any>): void;}