Write CSV data to a named file. If the file does not exist, it is created. If the file exists, it is truncated upon opening. Requires that file permissions be specified. Recommended permissions are 0600, 0622, and 0666 (6:rw, 4:w, 2:r).
(filename string, perm os.FileMode, rows [][]string)
source not stored for this graph (policy: none)