export interface WsUpgradeRequestOpts {
    /** Path + query string, e.g. `/ws?token=…&endpoint=…` (query param key kept for old servers). */
    upgradePath: string;
    host: string;
    port: number;
    /** Randomly generated Sec-WebSocket-Key (base64). */
    secWebSocketKey: string;
    /** Agent api_key — additionally sent as the X-Agent-Key header (preferred). */
    agentKey?: string;
}
/** Build the raw `GET … HTTP/1.1` WebSocket upgrade request string (CRLF-terminated). */
export declare function buildWsUpgradeRequest(opts: WsUpgradeRequestOpts): string;