import { HttpEvent, HttpRequest } from '@angular/common/http';
export interface HttpVisibilityInterceptorHttpEvent<T> {
    event: HttpEvent<T>;
    req: HttpRequest<T>;
    /**
     * Time in milliseconds since interceptor received the request.
     */
    duration: number;
}
export declare function isHttpVisibilityInterceptorHttpEvent<T>(event: HttpVisibilityInterceptorHttpEvent<T> | HttpVisibilityInterceptorError): event is HttpVisibilityInterceptorHttpEvent<T>;
export interface HttpVisibilityInterceptorError {
    err: unknown;
    req: HttpRequest<unknown>;
    /**
     * Time in milliseconds since interceptor received the request.
     */
    duration: number;
}
export declare function isHttpVisibilityInterceptorError(event: HttpVisibilityInterceptorHttpEvent<unknown> | HttpVisibilityInterceptorError): event is HttpVisibilityInterceptorError;