import { Request, Response, Sender } from "./types";
export interface AppendHeader {
    values: string[];
    separator: string;
}
export default class CustomHeaderSender {
    private sender;
    private customHeaders;
    private appendHeaders;
    constructor(innerSender: Sender, customHeaders: Record<string, string>, appendHeaders?: Record<string, AppendHeader>);
    send(request: Request): Promise<Response>;
}