import { type UnixUnit } from "../validate/isValidUnixUnit.js";
/**
 * Return the current Unix timestamp in either seconds or milliseconds.
 *
 * - Uses Temporal.Now.instant() to get current time.
 * - Defaults to "milliseconds" if no unit specified.
 * - Returns 0 on failure.
 *
 * @param unit optional unit specifier: "seconds" | "milliseconds"
 * @returns number (unix timestamp)
 *
 * @example getUnixNow() // 1700000000000
 * @example getUnixNow("seconds") // 1700000000
 */
export declare function getUnixNow(...unitInput: [unit?: UnixUnit]): number;