Unlocks the file or part of the file.
Unlocks the byte range from
end of the file, with
the byte at position
end not included. If no arguments are
specified, the full file is unlocked, If only
specified the file is unlocked from byte position
start to the
end of the file.
NOTE file locking does have slight differences in behavior across platforms:
See lock for more details.
Future<RandomAccessFile> unlock([int start = 0, int end = -1]);