/**
 * Return middleware that gets an unique request id from a header or
 * generates a new id.
 *
 * @param {Object} [options={}] - Optional configuration.
 * @param {string} [options.query] - Request query name to get the forwarded request id.
 * @param {string} [options.header=X-Request-Id] - Request header name to get the forwarded request id.
 * @param {string} [options.exposeHeader=X-Request-Id] - Response header name.
 * @param {function} [options.generator=uuidV4] - Id generator function.
 * @return {function} Koa middleware.
 */
export default function xRequestIdCreator(options?: {
    query?: string | undefined;
    header?: string | undefined;
    exposeHeader?: string | undefined;
    generator?: Function | undefined;
} | undefined): Function;