void unlockSync([int start = 0, int end = -1 ])

Synchronously unlocks the file or part of the file.

Unlocks the byte range from start to end of the file, with the byte at position end not included. If no arguments are specified, the full file is unlocked, If only start is 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 lockSync for more details.

Source

void unlockSync([int start = 0, int end = -1]);