/** 同一 chat 内 isolated scope 的并行门禁；非 isolated 不经过这里。 */
export declare class TopicConcurrencyLimiter {
    private readonly cap;
    private readonly running;
    private readonly deferred;
    constructor(cap?: number);
    tryAcquire(chatId: string, scopeKey: string): boolean;
    release(chatId: string, scopeKey: string): string[];
    hasRunning(chatId: string, scopeKey: string): boolean;
    runningCount(chatId: string): number;
    runningScopes(chatId: string): string[];
    private wakeDeferred;
    private runningSet;
    private deferredSet;
}