code: function _makeRequest(headers, options, data, callback) {
    var url = _.formatUrl(options);
    fetch(url, {
      method: 'POST',
      headers: headers,
      body: data
    })
    .then(function (resp) {
      return resp.json();
    })
    .then(function (data) {
      _handleResponse(data, _wrapPostCallback(callback));
    })
    .catch(function(err) {
      callback(err);
    });
  }
docs: Helpers *