/**
 * Takes an object with a hostname property (like a parsed URL) and some
 * headers that may contain Host and returns the preferred hostname.
 * @param parsed An object containing a hostname property.
 * @param headers A dictionary with headers containing a `host`.
 */
export declare function getHostname(parsed: {
    hostname?: string | null;
}, headers?: {
    [key: string]: string | string[] | undefined;
}): string | undefined;