import { HttpBackend, HttpClient, HttpEvent, HttpRequest } from '@angular/common/http';
import { Observable } from 'rxjs';
/**
 * Create an isolated HttpClient with a custom request/response handler
 * This bypasses the global HTTP_INTERCEPTORS
 */
export declare function createIsolatedHttpClient(backend: HttpBackend, transform: (req: HttpRequest<any>, next: (req: HttpRequest<any>) => Observable<HttpEvent<any>>) => Observable<HttpEvent<any>>): HttpClient;