import { Obj, GqlTransport, OperationContext, OperationResult } from '@pql/client';
import { Observable } from '@pql/observable';
export declare function noop(): void;
interface SocketOptions {
    url: string;
    timeout?: number;
    maxAttempts?: number;
    headers?: {
        [index: string]: string;
    };
    checkOnline?: boolean;
}
export declare class SocketTransport implements GqlTransport {
    private ws;
    private counter;
    private readonly max;
    private isOpen;
    private isReconnecting;
    private online;
    private readonly opts;
    private subscriptions;
    private lastid;
    private readonly unsub;
    constructor(opts: SocketOptions);
    private onlineChange;
    private onMessage;
    private open;
    private flushError;
    private reconnect;
    private json;
    execute<T = Obj, Vars = {}>(ctx: OperationContext<Vars>): Observable<OperationResult<T>>;
    setHeaders(headers: Obj): void;
    close(): Promise<void>;
}
export {};