/**
 * Blocking list waiters: BLPOP/BRPOP (SPEC_E).
 * In-memory wait queues by key; single delivery; wake on LPUSH/RPUSH.
 */
export type BlockKind = 'BLPOP' | 'BRPOP';
export type ConnectionId = string | number;
export type WaiterResolve = (value: [Buffer, Buffer] | null) => void;
/** Engine operations the manager needs to deliver elements on wake. */
export interface BlockingEngine {
    lpop(key: Buffer, count: null): unknown;
    rpop(key: Buffer, count: null): unknown;
}
export interface BlockingManagerOptions {
    maxWaitersPerKey?: number;
    maxTotalWaiters?: number;
    maxKeysPerWait?: number;
    clock?: () => number;
}
/**
 * @param engine - RESPlite engine (for lpop/rpop on wake)
 * @param opts - limits default to 10000 waiters per key, 50000 in total and 128 keys per wait; clock defaults to Date.now
 */
export declare function createBlockingManager(engine: BlockingEngine, opts?: BlockingManagerOptions): {
    deferWakeups(): void;
    flushWakeups(): void;
    registerWaiter: (keys: Buffer[], kind: BlockKind, timeoutSeconds: number, resolve: WaiterResolve, connectionId: ConnectionId) => {
        error?: string;
    };
    wakeup: (key: Buffer | string) => void;
    cancel: (connectionId: ConnectionId) => void;
    blockedClientCount: () => number;
};
export type BlockingManager = ReturnType<typeof createBlockingManager>;