import type { Server } from 'node:http';
import type { WebSocketChain, InjectWSOptions } from './internals.ts';
export type { WebSocketChain, InjectWSOptions };
/**
 * Synthetic WebSocket upgrade. Returns a `WebSocketChain` — call `.on(...)`
 * / `.once(...)` to queue listeners, then `await` (or `.connect()`) to
 * trigger the upgrade. The chain replays queued listeners onto the real
 * `WebSocket` BEFORE the handshake completes, so any frames the server
 * sends during the upgrade (e.g. an initial greeting) reach consumer
 * listeners reliably — no race window.
 *
 * The signature follows the platform convention (`new WebSocket(url)`,
 * `fetch(url)`, `new EventSource(url)`) rather than light-my-request's
 * options-bag form, since URL is effectively the only first-class
 * request property for a WebSocket upgrade.
 */
export declare function injectWS(server: Server, url?: string, options?: InjectWSOptions): WebSocketChain;