/**
 * A custom Error type for errors that occur during a `fetch()` request.
 * Includes the `Response` object and optional response data for more detailed error analysis.
 *
 * @example
 * ```typescript
 * try {
 *   const response = await fetch('/some/url')
 *
 *   if (!response.ok) {
 *      const data = await response.json(); // Attempt to parse JSON error data
 *      throw new FetchError(response, data)
 *   }
 *   // ... process successful response
 * } catch (error) {
 *   if (error instanceof FetchError) {
 *     console.error("Fetch error:", error.message, error.response.status, error.data)
 *   } else {
 *     console.error("Other error:", error)
 *   }
 * }
 * ```
 */
export declare class FetchError extends Error {
    response: Response;
    data?: unknown;
    constructor(response: Response, data?: unknown);
}