Interface IEventEmitter

interface IEventEmitter {
    emit: (event: Event) => Promiseable<void> & (
        event: CustomEvent,
    ) => Promiseable<void> & (
        event: string,
        ...args: unknown[],
    ) => Promiseable<void>;
    off: (event: Event, listener: FunctionalEventListener) => void & (
        event: string,
        listener: FunctionalEventListener,
    ) => void & (event: CustomEvent, listener: FunctionalEventListener) => void;
    on: (event: Event, listener: FunctionalEventListener) => void & (
        event: string,
        listener: FunctionalEventListener,
    ) => void & (event: CustomEvent, listener: FunctionalEventListener) => void;
}