export declare class RequestActivityTracker {
    private readonly byRequestId;
    private readonly tmuxCounts;
    private readonly ttlMs;
    private readonly maxEntries;
    private removeRecord;
    private prune;
    start(requestId: string, metadata?: Record<string, unknown> | null): void;
    end(requestId: string): void;
    countActiveRequestsForTmuxSession(tmuxSessionId: string): number;
}