code: public boolean isEmpty() {
  		return _name == null &&
  			_comment == null &&
  			_description == null &&
  			_source == null &&
  			_links.isEmpty() &&
  			_number == null &&
  			(_segments.isEmpty() ||
  				_segments.stream().allMatch(TrackSegment::isEmpty));
  	}
docs: Return {@code true} if all track properties are {@code null} or empty.
  
  @return {@code true} if all track properties are {@code null} or empty