/** Scheduling policy for read-only polling; never sends or replays a request. */
export declare class PollingBackoff {
    private readonly intervalMs;
    private failures;
    private nextAt;
    constructor(intervalMs: number);
    reset(): void;
    failed(error: unknown): void;
    /** Zero means ready, false means stop, otherwise wait at least this many ms. */
    waitMs(): number | false;
}