# Open this file for reading.
	#
	# ~~~
	# var file = "/etc/issue".to_path.open_ro
	# print file.read_line
	# file.close
	# ~~~
	#
	# Note that it is the user's responsibility to close the stream.
	# Therefore, for simple use case, look at `read_all` or `each_line`.
	#
	# ENSURE `last_error == result.last_error`
	fun open_ro: FileReader
	do
		var res = new FileReader.open(path)
		last_error = res.last_error
		return res
	end