BinFile = function(path) {
  /**
   * File handle.
   * @type {number}
   * @private
   */
  this.fd_ = fs.openSync(path, 'w');

  /**
   * Current offset into the file.
   * @type {number}
   * @private
   */
  this.offset_ = 0;
}
Binary file wrapper.
@param {string} path File path.
@constructor