export declare function normalizeSfuWsUrl(raw: string): string;
export declare function getCachedSfuUrl(host: string): string | null;
/**
 * Pings the SFU health endpoints in parallel and returns the WebSocket URL whose server
 * answered fastest. Falls back to the first URL if every ping fails or times out.
 */
export declare function selectBestSfuUrl(requestedUrls: string[], host?: string): Promise<string>;
/**
 * Fire-and-forget: run the SFU ping and cache so the result is ready when somebody joins a
 * voice channel. Called from the server:details handler.
 */
export declare function warmSfuSelection(host: string, sfuHosts: string[]): void;