type DeferredState = "pending" | "fulfilled" | "rejected";
declare class Deferred<T> extends Promise<T> {
    readonly state: DeferredState;
    readonly value?: T;
    readonly reason?: unknown;
    resolve: (value: T | PromiseLike<T>) => void;
    reject: (reason?: unknown) => void;
    constructor(executor?: (resolve: (value: T | PromiseLike<T>) => void, reject: (reason?: unknown) => void) => void);
}

interface CdpConnectionOptions {
    url?: string | URL | undefined;
    target?: string | undefined;
}
interface CdpMessageEventInit<T = unknown> extends EventInit {
    method: string;
    params: T;
}
declare class CdpMessageEvent<T = unknown> extends Event {
    readonly method: string;
    readonly params: T;
    constructor(init: CdpMessageEventInit<T>);
}
interface CdpConnectionEventMap {
    message: CdpMessageEvent;
}
declare class CdpError extends Error {
    code: number;
    constructor(code: number, message: string, options?: ErrorOptions | undefined);
}
declare class CdpConnection extends EventTarget {
    #private;
    static create(options?: CdpConnectionOptions | undefined): Promise<CdpConnection>;
    private constructor();
    send(method: string, params?: unknown): Deferred<unknown>;
    close(): void;
    addEventListener<T extends keyof CdpConnectionEventMap>(type: T, listener: (this: WebSocket, event: CdpConnectionEventMap[T]) => unknown, options?: boolean | AddEventListenerOptions): void;
    addEventListener(type: string, listener: (this: WebSocket, event: Event) => unknown, options?: boolean | AddEventListenerOptions): void;
    removeEventListener<T extends keyof CdpConnectionEventMap>(type: T, listener: (this: WebSocket, event: CdpConnectionEventMap[T]) => unknown, options?: boolean | EventListenerOptions): void;
    removeEventListener(type: string, listener: (this: WebSocket, event: Event) => unknown, options?: boolean | EventListenerOptions): void;
}
declare function createCdpConnection(options?: CdpConnectionOptions | undefined): Promise<CdpConnection>;

export { CdpConnection, CdpConnectionEventMap, CdpConnectionOptions, CdpError, CdpMessageEvent, CdpMessageEventInit, createCdpConnection };