interface SSEOptions {
    readonly withCredentials?: boolean;
    readonly eventSource?: SSEConstructor;
    readonly onOpen?: (event: Event) => void;
    readonly onMessage?: (event: MessageEvent) => void;
    readonly onError?: (event: Event) => void;
}
interface SSEClient {
    readonly source: EventSource;
    close(): void;
}
type SSEConstructor = new (url: string, options?: EventSourceInit) => EventSource;
declare function createSSE(url: string, options?: SSEOptions): SSEClient;
interface WebSocketOptions {
    readonly protocols?: string | readonly string[];
    readonly webSocket?: WebSocketConstructor;
    readonly autoReconnect?: boolean;
    readonly reconnectDelay?: number;
}
interface WebSocketClient {
    readonly socket: WebSocket | null;
    readonly state: WebSocketState;
    connect(): void;
    send(data: string | ArrayBufferLike | Blob | ArrayBufferView): void;
    close(code?: number, reason?: string): void;
    on<K extends WebSocketEventName>(event: K, listener: WebSocketEventListener<K>): () => void;
}
type WebSocketState = 'idle' | 'connecting' | 'open' | 'closed';
type WebSocketEventName = 'open' | 'message' | 'error' | 'close';
type WebSocketEventListener<K extends WebSocketEventName> = K extends 'message' ? (event: MessageEvent) => void : K extends 'close' ? (event: CloseEvent) => void : (event: Event) => void;
type WebSocketConstructor = new (url: string, protocols?: string | string[]) => WebSocket;
declare function createWebSocket(url: string, options?: WebSocketOptions): WebSocketClient;

export { type SSEClient, type SSEConstructor, type SSEOptions, type WebSocketClient, type WebSocketConstructor, type WebSocketEventListener, type WebSocketEventName, type WebSocketOptions, type WebSocketState, createSSE, createWebSocket };