export declare class CustomError extends Error {
}
export declare class CustomErrorEvent extends Event {
    error: CustomError;
    message: string;
    constructor(message: string, error: CustomError);
}
export declare class CustomMessageEvent extends MessageEvent<{
    url: string;
    position: number;
    chunk?: Uint8Array;
    isAppending?: boolean;
    fileArraybuffer?: Uint8Array;
    totalLength: number;
    offsets?: {
        startByte: number;
        endByte: number;
    };
}> {
}