/**
 * @example 并发控制类
 *
 * const concurrent = new Concurrent(3); // 3个并发
 *
 * // 模拟10个异步任务
 * for (let i = 0; i < 10; i++) {
 *   concurrent.append(() => {
 *     return new Promise((resolve) => {
 *       console.log(`开始任务 ${i}`)
 *       setTimeout(() => {
 *         console.log(`结束任务 ${i}`)
 *         resolve(true)
 *       }, 1000)
 *     })
 *   })
 * }
 *
 */
export declare class Concurrent {
    /** 并发数量 */
    private total;
    /** 当前并发数量 */
    private count;
    /** 等待执行任务 */
    private peddings;
    constructor(total: number);
    append(fn: () => Promise<any>): void;
    private run;
}