Method intercept

packages/common/http/test/provider_spec.ts:800–802

(req: HttpRequest<any>, next: HttpHandler)

function provideLegacyInterceptor(tag: string): Provider {
  class LegacyTagInterceptor implements HttpInterceptor {
    intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
      return next.handle(addTagToRequest(req, tag));
    }
  }

  const token = new InjectionToken(`LegacyTagInterceptor[${tag}]`, {