/**
 * Deferred promise utility — maps Python's asyncio.Future for the RELAY client.
 *
 * Uses a manual promise constructor for Node 18+ compatibility.
 */
/**
 * A promise with externalised `resolve`/`reject` and a `settled` flag,
 * used by the RELAY client to bridge server-push events back to in-flight
 * JSON-RPC request callers.
 */
export interface Deferred<T> {
    /** The wrapped promise. */
    promise: Promise<T>;
    /** Resolve the promise idempotently (later calls are ignored). */
    resolve: (value: T | PromiseLike<T>) => void;
    /** Reject the promise idempotently (later calls are ignored). */
    reject: (reason?: unknown) => void;
    /** True once either `resolve` or `reject` has been called. */
    readonly settled: boolean;
}
/**
 * Create a {@link Deferred} with externalised `resolve` / `reject` and a
 * `settled` flag.
 *
 * The returned object exposes the promise plus its resolve and reject
 * functions so callers outside the executor can settle it. Later calls to
 * `resolve` or `reject` are idempotent.
 *
 * @typeParam T - Resolution value type of the wrapped promise.
 * @returns A fresh `Deferred<T>` in pending state.
 */
export declare function createDeferred<T>(): Deferred<T>;
/**
 * Race a promise against a timeout.
 *
 * @typeParam T - Resolution value type of the input promise.
 * @param promise - Promise to race against the timeout.
 * @param ms - Timeout in milliseconds.
 * @param label - Label used in the timeout error message. Defaults to
 *   `"Operation"`.
 * @returns A new promise that resolves with `promise`'s value if it settles
 *   before the timeout, and rejects with a timeout `Error` otherwise.
 */
export declare function withTimeout<T>(promise: Promise<T>, ms: number, label?: string): Promise<T>;