/**
 * Starting at the `start` port, look for a free port incrementing
 * by 1 until `end` inclusive. If no port is found error is thrown.
 *
 * @param {number} start
 * @param {number} end
 * @param {number} port
 * @returns {Promise<number>}
 * @throws
 */
export declare function findFreePort(start?: number, end?: number, port?: number): Promise<number>;