/**
 * Per-client schema-fence watcher. Watches the fence via the injected
 * {@link CoordinationProvider}; on `draining` it drains in-flight writes
 * and reports presence (its ack); emits a same-instance signal on every
 * state transition (for UI). Driven by an interval in production and by
 * explicit `check()`/`beat()` in tests.
 *
 * The transport is the coordination port: the default
 * {@link StoreCoordinationProvider} maps `reportPresence` →
 * `_meta/schema-fence:client:<id>` and `readFence` → `_meta/schema-fence`,
 * so behavior is byte-for-byte the same; `by-tabs` / `by-peer` swap in
 * real-time push transports.
 */
import { type FenceState } from './fence.js';
import type { CoordinationProvider } from '../../port/by/index.js';
export interface FenceWatcherEvent {
    readonly currentSchemaVersion: number;
    readonly fenceState: FenceState;
}
export declare class FenceWatcher {
    #private;
    constructor(opts: {
        coordination: CoordinationProvider;
        vault: string;
        clientId: string;
        sessionId?: string;
        onFlush: () => Promise<void>;
        now?: () => number;
        emit?: (e: FenceWatcherEvent) => void;
    });
    /** Publish liveness (and the current ack) without changing quiesce state. */
    beat(): Promise<void>;
    /** Poll the fence; quiesce on draining; emit on transitions. */
    check(): Promise<void>;
    start(intervalMs: number): void;
    stop(): void;
}