message: imp(core): use.operator type inference
diff: @@ -3,9 +3,9 @@ import { switchMap } from 'rxjs/operators';
  import { Middleware } from '../../effects/effects.interface';
  import { HttpRequest, HttpResponse } from '../../http.interface';
  -export const use = <T extends HttpRequest>
  - (middleware: Middleware<HttpRequest, T>, res?: HttpResponse) =>
  - (source$: Observable<HttpRequest>): Observable<T> =>
  +export const use = <I extends HttpRequest, O extends HttpRequest>
  + (middleware: Middleware<I, O>, res?: HttpResponse) =>
  + (source$: Observable<I>): Observable<O> =>
  source$.pipe(
  switchMap(req => middleware(of(req), res!, {}))
  );
  