/**
 * @license
 * Copyright 2025 Steven Roussey <sroussey@gmail.com>
 * SPDX-License-Identifier: Apache-2.0
 */
export interface HybridManagerOptions {
    /** Default polling interval in milliseconds for backup polling */
    readonly defaultIntervalMs?: number;
    /** Backup polling interval in milliseconds (0 to disable, default: 5000) */
    readonly backupPollingIntervalMs?: number;
    /** Enable BroadcastChannel notifications (default: true) */
    readonly useBroadcastChannel?: boolean;
    /** BroadcastChannel name for cross-tab communication */
    readonly broadcastChannelName?: string;
}
import type { ChangeCallback, ChangePayloadFactory, ItemComparator, StateFetcher } from "./PollingSubscriptionManager";
export interface HybridSubscriptionOptions {
    /** Polling interval in milliseconds (not used if BroadcastChannel is active). */
    readonly intervalMs?: number;
}
/**
 * Combines three notification mechanisms behind a single subscription API:
 * local events (same-tab), BroadcastChannel (cross-tab, near-instant), and an
 * optional backup poll. Falls back to local events only when BroadcastChannel
 * is unavailable.
 */
export declare class HybridSubscriptionManager<Item, Key, ChangePayload> {
    private readonly subscribers;
    private lastKnownState;
    private initialized;
    private channel;
    private backupPollingIntervalId;
    private readonly fetchState;
    private readonly compareItems;
    private readonly payloadFactory;
    private readonly options;
    private readonly hasBroadcastChannel;
    constructor(channelName: string, fetchState: StateFetcher<Item, Key>, compareItems: ItemComparator<Item>, payloadFactory: ChangePayloadFactory<Item, ChangePayload>, options?: HybridManagerOptions);
    private initializeBroadcastChannel;
    private handleBroadcastMessage;
    /** Must be called after any local mutation. */
    notifyLocalChange(): void;
    subscribe(callback: ChangeCallback<ChangePayload>, options?: HybridSubscriptionOptions): () => void;
    private initAndNotify;
    private notifySubscriberOfCurrentState;
    private pollAndNotify;
    private startBackupPolling;
    private stopBackupPolling;
    get subscriptionCount(): number;
    get hasSubscriptions(): boolean;
    get isBroadcastChannelActive(): boolean;
    destroy(): void;
}
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