import debug from "debug";
import type { NewBrowser } from "../browser/new-browser";
import { AsyncEmitter } from "../events";
import { BrowserOpts, Pool, PoolObserver } from "./types";
import { Config } from "../config";
export declare class BasicPool implements Pool {
    private _config;
    private _emitter;
    private _activeSessions;
    private _cancelled;
    private _cancelError;
    private _wdPool;
    private _observer?;
    log: debug.Debugger;
    static create(config: Config, emitter: AsyncEmitter, observer?: PoolObserver): BasicPool;
    constructor(config: Config, emitter: AsyncEmitter, observer?: PoolObserver);
    getBrowser(id: string, opts?: BrowserOpts): Promise<NewBrowser>;
    freeBrowser(browser: NewBrowser): Promise<void>;
    private _emit;
    cancel(err?: Error): void;
}