code: function RotatingFileHandler(filename, mode, maxBytes, backupCount,
                               encoding, delay) {
  	mode = mode || 'a';
  	maxBytes = typeof maxBytes !== 'undefined' ? maxBytes : 0;
  	backupCount = typeof backupCount !== 'undefined' ? backupCount : 0;
  	encoding = typeof encoding !== 'undefined' ? encoding : 'utf8';
  	delay = typeof delay !== 'undefined' ? delay : false;
  
  	if (maxBytes > 0) {
  		mode = 'a';
  	}
  
  	FileHandler.call(this, filename, mode, encoding, delay);
  
  	/**
  	 * @private
  	 * @type {number}
  	 */
  	this._maxBytes = maxBytes;
  
  	/**
  	 * @private
  	 * @type {number}
  	 */
  	this._backupCount = backupCount;
  
  	/**
  	 * @private
  	 * @type {Promise}
  	 */
  	this._chain = Promise.resolve();
  }
docs: Handler for logging to a set of files, which switches from one file
  to the next when the current file reaches a certain size.
  
  @constructor RotatingFileHandler
  @extends FileHandler
  @param {string} filename
  @param {string} [mode=a]
  {@link https://nodejs.org/api/fs.html#fs_fs_open_path_flags_mode_callback}
  @param {number} [maxBytes=0]
  @param {number} [backupCount=0]
  @param {string} [encoding=utf8]
  {@link https://nodejs.org/api/buffer.html#buffer_buffers_and_character_encodings}
  @param {boolean} [delay=false]