/**
 * Copyright (c) Facebook, Inc. and its affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * @flow
 */
export declare function useSyncExternalStore<T>(subscribe: (fn: () => void) => () => void, getSnapshot: () => T, getServerSnapshot?: () => T): T;