How to use the fbjs/lib/Deferred function in fbjs

async function run(options) {
  const serverOptions = {
    host: options.host,
    port: options.port,
  };

  if (!isClient) {
    const deferred = new Deferred();
    const server = new RSocketServer({
      getRequestHandler: socket => {
        runOperation(socket, options);
        return new SymmetricResponder();
      },
      transport: getServerTransport(options.protocol, serverOptions),
    });
    server.start();

    console.log(`Server started on ${options.host}:${options.port}`);
    return deferred.getPromise();
  } else {
    console.log(`Client connecting to ${options.host}:${options.port}`);
    // $FlowFixMe
    const socket: ReactiveSocket = await connect(
      options.protocol,

constructor(socket: ws.Socket, encoders: ?Encoders<*>) {
    this._active = true;
    this._close = new Deferred();
    this._encoders = encoders;
    this._socket = socket;
    this._statusSubscribers = new Set();

    if (socket) {
      this._status = CONNECTION_STATUS.CONNECTED;
    } else {
      this._status = CONNECTION_STATUS.NOT_CONNECTED;
    }

    // If _receiver has been `subscribe()`-ed already
    let isSubscribed = false;
    this._receiver = new Flowable(subscriber => {
      invariant(
        !isSubscribed,
        'RSocketWebSocketServer: Multicast receive() is not supported. Be sure ' +

function runOperation(socket, options) {
  const deferred = new Deferred();
  let subscription: ISubscription;
  doOperation(socket, options.operation, options.payload).subscribe({
    onComplete() {
      console.log('onComplete()');
      deferred.resolve();
    },
    onError(error) {
      console.log('onError(%s)', error.message);
      deferred.reject(error);
    },
    onNext(payload) {
      console.log('onNext(%s)', payload.data);
    },
    onSubscribe(_subscription) {
      subscription = _subscription;
      subscription.request(MAX_STREAM_ID);

awaitN(n: number): Promise {
    this._payloadCount = n;
    this._payloadDefer = new Deferred();
    return this._payloadDefer.getPromise();
  }

constructor(log: Function) {
    this._cancelled = false;
    this._completeDefer = new Deferred();
    this._completed = false;
    this._errorDefer = new Deferred();
    this._errored = false;
    this._log = log;
    this._payloadCount = null;
    this._payloadDefer = null;
    this._payloads = [];
    this._subscription = null;
  }

constructor(log: Function) {
    this._cancelled = false;
    this._completeDefer = new Deferred();
    this._completed = false;
    this._errorDefer = new Deferred();
    this._errored = false;
    this._log = log;
    this._payloadCount = null;
    this._payloadDefer = null;
    this._payloads = [];
    this._subscription = null;
  }

export function genMockConnection() {
  const deferred = new Deferred();
  const receiver = genMockPublisher();
  const status = genMockPublisher();
  let closed = false;

  const connection = {
    close: jest.fn(() => {
      connection.mock.close();
    }),
    connect: jest.fn(),
    connectionStatus: jest.fn(() => status),
    onClose: jest.fn(() => {
      return deferred.getPromise();
    }),
    receive: jest.fn(() => receiver),
    send: jest.fn(frames => {
      connection.send.mock.frames = frames;

constructor(log: Function) {
    this._cancelled = false;
    this._completeDefer = new Deferred();
    this._completed = false;
    this._errorDefer = new Deferred();
    this._errored = false;
    this._log = log;
    this._payloadCount = null;
    this._payloadDefer = null;
    this._payloads = [];
    this._subscription = null;
  }