import { EventUnsubscribe } from './event';
export interface CancellationToken {
    /**
     * A flag signalling is cancellation has been requested.
     */
    readonly isCancellationRequested: boolean;
    /**
     * An event which fires when cancellation is requested. This event
     * only ever fires `once` as cancellation can only happen once. Listeners
     * that are registered after cancellation will be called (next event loop run),
     * but also only once.
     *
     * @event onCancellationRequested
     */
    readonly onCancellationRequested: (listener: (e: any) => any, thisArgs?: any, unsubs?: EventUnsubscribe[]) => EventUnsubscribe;
}
export declare namespace CancellationToken {
    function isCancellationToken(thing: unknown): thing is CancellationToken;
    const None: CancellationToken;
    const Cancelled: CancellationToken;
}
export declare class CancellationTokenSource {
    private readonly _parentUnsubscribe?;
    constructor(parent?: CancellationToken);
    private _token?;
    get token(): CancellationToken;
    cancel(): void;
    dispose(cancel?: boolean): void;
}