import { SdError } from "../errors/SdError";
import EventEmitter from "events";
export declare class SdAsyncFnSerialQueue extends EventEmitter {
    private readonly _gap;
    private readonly _queue;
    private _isQueueRunning;
    on(event: "error", listener: (err: SdError) => void): this;
    constructor(_gap?: number);
    run(fn: () => void | Promise<void>): void;
    private _processAsync;
}