type WidgetTokenFetcher = () => Promise<{
    widgetToken: string;
    exp?: number;
}>;
type WidgetTokenState = {
    status: 'loading';
} | {
    status: 'ready';
    widgetToken: string;
    exp?: number;
    isRefreshing: boolean;
    lastError?: unknown;
} | {
    status: 'error';
    error: unknown;
};
interface WidgetTokenManager {
    start(): void;
    stop(): void;
    refresh(): Promise<void>;
    getState(): WidgetTokenState;
    subscribe(listener: () => void): () => void;
}
interface CreateWidgetTokenManagerOptions {
    fetcher: WidgetTokenFetcher;
    /** Refresh `leadSeconds` before `exp`. Default 60. */
    leadSeconds?: number;
}
declare function createWidgetTokenManager(options: CreateWidgetTokenManagerOptions): WidgetTokenManager;

export { createWidgetTokenManager };
export type { CreateWidgetTokenManagerOptions, WidgetTokenFetcher, WidgetTokenManager, WidgetTokenState };