export declare class AccessToken {
    readonly accessToken: string;
    readonly expireTime: number;
    constructor(accessToken: string, expireTime: number);
    isValid(): boolean;
    toJSON(): {
        accessToken: string;
        expireTime: number;
    };
    static fromJSON(value: any): AccessToken | null;
}
export interface TokenStorage {
    load(): Promise<AccessToken | null>;
    save(token: AccessToken | null): Promise<void>;
}
/**
 * @internal
 */
export declare class MemoryTokenStorage implements TokenStorage {
    private token;
    load(): Promise<AccessToken | null>;
    save(token: AccessToken | null): Promise<void>;
}