function loadFile(file, options, callback) {
  const promise = graph.loadFile(file)
    .then((graphInstance) => createNetwork(graphInstance, options));
  if (callback) {
    deprecated('Providing a callback to NoFlo.loadFile is deprecated, use Promises');
    promise.then((network) => {
      callback(null, network);
    }, callback);
  }
  return promise;
}
@param {string} file
@param {NetworkOptions} options - Network options
@param {any} [callback] - Legacy callback
@returning {Promise<Network>}