code: function signedRequestHeaders(apiKey, apiSecretKey, apiUserToken, options) {
    if (!apiKey || !apiSecretKey || !apiUserToken) {
      return false;
    }
    var apiExpDate = Math.floor(Date.now() / 1000) + 600;
    var payload = apiKey + apiUserToken + apiExpDate;
    var hash = CryptoJS.HmacSHA256(payload, apiSecretKey);
    var headers = {
      'x-api-key': apiKey,
      'x-api-user-token': apiUserToken,
      'x-api-signature': 'Method=HMAC-SHA256 Signature=' + hash,
      'x-api-exp-date': apiExpDate,
    };
    return headers;
  }
docs: Return an Object of headers to attach to a request