export default class Event {
    _eventMap: Map<string, ((...arg: any) => void)[]>;
    on(event: string, callback: (...arg: any) => void): this;
    once(event: string, callback: (...arg: any) => void): void;
    off(event: string, callback?: null | (() => void)): this;
    emit(event: string, ...args: any[]): boolean;
}