import { API } from '../../api';
import { IAttachmentOptions, AttachmentFactoryOptions } from './attachment';
import { kSerializeData, AttachmentType } from '../../utils/constants';
export type IExternalAttachmentOptions<P, Type extends string = string> = IAttachmentOptions<P, Type>;
export type ExternalAttachmentFactoryOptions<P> = AttachmentFactoryOptions<P>;
export declare class ExternalAttachment<P = object, Type extends string | AttachmentType = string> {
    type: Type;
    protected $filled: boolean;
    protected api: API;
    protected payload: P;
    /**
     * Constructor
     */
    constructor(options: IExternalAttachmentOptions<P, Type>);
    /**
     * Returns custom tag
     */
    get [Symbol.toStringTag](): string;
    /**
     * Returns whether the attachment is filled
     */
    get isFilled(): boolean;
    /**
     * Can be attached via string representation
     */
    get canBeAttached(): boolean;
    /**
     * Returns data for JSON
     */
    toJSON(): object;
    /**
     * Returns the custom data
     */
    [kSerializeData](): object;
}