declare type TaskResult<T> = {
    kind: "resolved";
    value: T;
} | {
    kind: "discarded";
};
interface QueueController {
    discard(): void;
}
export declare class ControlledQueue {
    private queue;
    private queueLoopPromise;
    private discardQueue;
    private queueLoop;
    exec<T>(pfn: (controller: QueueController) => Promise<T>): Promise<TaskResult<T>>;
}
export {};