# Last error produced by I/O operations.
	#
	# ~~~
	# var path = "/does/not/exists".to_path
	# assert path.last_error == null
	# path.read_all
	# assert path.last_error != null
	# ~~~
	#
	# Since `Path` objects are stateless, `last_error` is reset on most operations and reflect its status.
	var last_error: nullable IOError = null is writable