/**
 * Owns timers + unload hooks for the automatic snapshot cadence. Distinct from
 * the sync `SyncScheduler` (whose push/pull/dirty-count shape doesn't map to
 * snapshots) — it borrows only the policy vocabulary. Delegates the actual
 * snapshot work to `callbacks.fire()`.
 */
import type { SnapshotPolicy } from './policy.js';
export interface SnapshotSchedulerCallbacks {
    /** Fire one auto-snapshot cycle (per dirty vault). Swallows its own per-vault errors. */
    fire(): Promise<void>;
    /** Number of vaults with pending writes since the last fire. */
    pendingCount(): number;
}
export declare class SnapshotScheduler {
    private readonly policy;
    private readonly callbacks;
    private debounceTimer;
    private intervalTimer;
    private lastFireTime;
    private firing;
    private started;
    private readonly boundVisibility;
    private readonly boundUnload;
    constructor(policy: SnapshotPolicy, callbacks: SnapshotSchedulerCallbacks);
    start(): void;
    stop(): void;
    notifyChange(): void;
    private resetDebounce;
    private execFire;
    private handleVisibility;
    private handleUnload;
    private flush;
    private shouldRegisterUnload;
}