/**
 * DTO for file attachments
 * Used for sending attached files with emails
 */
export declare class AttachmentDto {
    /**
     * The name of the attached file
     */
    filename: string;
    /**
     * The content of the file in Base64 encoding
     */
    content: string;
    /**
     * The content type of the file (MIME type)
     */
    contentType?: string;
}