/// <reference types="node" />
/// <reference types="node" />
/// <reference types="node" />
import { EventEmitter } from 'events';
import { LookupFunction } from 'net';
import { CheckAddressFunction } from './HttpAgent';
import { RequestURL, RequestOptions } from './Request';
import { HttpClientResponse } from './Response';
export declare type ClientOptions = {
    defaultArgs?: RequestOptions;
    /**
     * Custom DNS lookup function, default is `dns.lookup`.
     */
    lookup?: LookupFunction;
    /**
      * check request address to protect from SSRF and similar attacks.
      * It receive two arguments(ip and family) and should return true or false to identified the address is legal or not.
      * It rely on lookup and have the same version requirement.
      */
    checkAddress?: CheckAddressFunction;
    connect?: {
        key?: string | Buffer;
        /**
        * A string or Buffer containing the certificate key of the client in PEM format.
        * Notes: This is necessary only if using the client certificate authentication
        */
        cert?: string | Buffer;
        /**
        * If true, the server certificate is verified against the list of supplied CAs.
        * An 'error' event is emitted if verification fails.Default: true.
        */
        rejectUnauthorized?: boolean;
    };
};
export declare const HEADER_USER_AGENT: string;
export declare class HttpClient extends EventEmitter {
    #private;
    constructor(clientOptions?: ClientOptions);
    request(url: RequestURL, options?: RequestOptions): Promise<HttpClientResponse>;
}