import { NoArgsWithoutReturnFunctionType, SubscriberCbType } from "./Observable";
import { NotifyTypeEn, SubscriptionObserver } from "./SubscriptionObserver";
export declare enum SubscriptionStateEn {
    INITIALIZING = "initializing",
    RUNNING = "running",
    BUFFERING = "buffering",
    READY = "ready",
    CLOSED = "closed"
}
export interface ObserverCbType<T> {
    nextCb: (val?: T) => void;
    completeCb?: NoArgsWithoutReturnFunctionType;
}
export declare class Subscription<T> {
    _subscriptionObserver: SubscriptionObserver<T>;
    /**
     * 订阅状态：
     *   initializing: 初始化
     *   buffering: 缓存新消息过程中，结束后通过微任务统一处理
     *   running: 在执行 next / complete 过程中
     *   ready: 准备就绪，等待接收新消息到来，并执行 observerCb
     *   closed: 订阅结束，不再对到来的新消息执行 observerCb
     */
    _state: SubscriptionStateEn;
    _queue: {
        type: NotifyTypeEn;
        value?: T;
    }[];
    _observerCb?: ObserverCbType<T>;
    _cleanupCb?: NoArgsWithoutReturnFunctionType | void;
    constructor(observerCb: ((val?: T) => void) | ObserverCbType<T>, subscriberCb: SubscriberCbType<T>);
    /** 判断本次订阅是否已经关闭 */
    get isClosed(): boolean;
    /**
     * 关闭订阅，清理 subscription 内部维护的状态
     */
    unsubscribe(): void;
}