/**
 * One background poller per key, shared by every subscriber.
 *
 * The app's daemon runs one session per window, and each window used to poll
 * its repo on its own: git status every 5s, GitHub issue/PR counts every 60s,
 * CI every 15–60s. Two windows on the same repo did all of it twice. Here the
 * first subscriber for a key starts the poller, later ones join it (and get
 * the last value at once), and the last one to leave stops it.
 */
/** A running poller: `refresh` asks for a check now, `stop` ends it for good. */
export interface Poller {
    refresh(): void | Promise<void>;
    stop(): void;
}
export interface SharedSubscription {
    /** Check now (e.g. after an agent run). Shared: one check serves every subscriber. */
    refresh(): void;
    /** Leave. The poller stops when its last subscriber leaves. */
    unsubscribe(): void;
}
export interface SharedPolls<T> {
    subscribe(key: string, listener: (value: T) => void): SharedSubscription;
    /** Number of running pollers. */
    size(): number;
}
export declare function createSharedPolls<T>(start: (key: string, publish: (value: T) => void) => Poller): SharedPolls<T>;
/**
 * Fixed-cadence poller: first check after `firstDelayMs`, then every
 * `intervalMs` after the previous check settles. `fetch` returning null (or
 * throwing) publishes nothing, so subscribers keep their last-known value.
 */
export declare function startIntervalPoll<T>(opts: {
    fetch: () => Promise<T | null>;
    publish: (value: T) => void;
    firstDelayMs: number;
    intervalMs: number;
}): Poller;