/**
 * Returns a deterministic UUID v4 string. The value is derived from the
 * current execution counter, producing the **same UUID** on every replay.
 *
 * Use this instead of `crypto.randomUUID()` inside workflow functions.
 *
 * ```typescript
 * const id = Durable.workflow.uuid4();
 * // e.g. "a3b8f042-1e9c-4d5a-b6e7-3f2c8a9d0e1b"
 * ```
 *
 * @returns {string} A deterministic UUID v4 string.
 */
export declare function uuid4(): string;