/**
 * -------------------------
 * Q: Why not use 'setTimeout'?
 * -------------------------
 * A: setTimeout can be paused (e.g., during hibernation), risking JWT expiration before it triggers.
 *    We therefore use a scheduler to check wall-clock time every second and execute the callback at the scheduled time.
 * -------------------------
 */
export declare class Scheduler {
    private callbacks;
    private nextId;
    private intervalId;
    schedule(epoch: number, callback: () => void): number;
    unschedule(handle: number): void;
    private startInterval;
    private stopInterval;
    private checkCallbacks;
}